My Network Lab: Configuring BGP with Default Routing

There are four common BGP/ISP designs:
* Single-homed (1 link per ISP, 1 ISP)
* Dual-homed (2+ links per ISP, 1 ISP)
* Single-multihomed (1 link per ISP, 2+ ISPs)
* Dual-multihomed (2+ links per ISP, 2+ ISPs)

Single-homed designs often use one of two options for routing to and from the Internet:
* Use static routes (default in the enterprise, and a static route for the enterprise’s public address range at the ISP).
* Use BGP, but only to exchange a default route (ISP to enterprise) and a route for the enterprise’s public prefix (enterprise to ISP). For a dual-homed case, the second link gives the enterprise a choice.

The common cases when using defaults works well, ignoring BGP, are:
* To prefer one Internet connection over another for all destinations, but when the better ISP connection fails, all traffic reroutes over the secondary connection.
* To treat both Internet connections as equal, sending packets for some destinations out each path. However, when one fails, all traffic reroutes over the one still-working path.

A single-multihomed topology means a single link per ISP, but multiple (at least two) ISPs.

The last general category of Internet access topologies is called dual-multihomed. With this design, two or more ISPs are used, with two or more connections to each. A number of different routers can be used.

To help reduce the memory requirements of receiving full BGP updates (BGP updates that include all routes), some ISPs give you three basic options for what routes the ISP advertises:
* Default route only: The ISP advertises a default route with BGP, but no other routes.
* Full updates: The ISP sends you the entire BGP table.
* Partial updates: The ISP sends you routes for prefixes that might be better reached through that ISP, but not all routes, plus a default route (to use as needed instead of the purposefully omitted routes).

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#interface loop 0

R1(config-if)#

*Jul 13 10:33:16.491: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up

R1(config-if)#ip address 10.1.1.1 255.255.255.0

R1(config-if)#

R1(config-if)#interface serial 2/0

R1(config-if)#ip address 10.0.0.1 255.255.255.252

R1(config-if)#no shut

R1(config-if)#

*Jul 13 10:33:51.027: %LINK-3-UPDOWN: Interface Serial2/0, changed state to up

R1(config-if)#

*Jul 13 10:33:52.035: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/0, changed state to up

R1(config-if)#end

R1#

R2#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R2(config)#interface loop 0

R2(config-if)#

*Jul 13 10:34:30.375: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up

R2(config-if)#ip address 192.168.0.1 255.255.255.0

R2(config-if)#

R2(config-if)#interface loop 1

R2(config-if)#

*Jul 13 10:34:45.047: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback1, changed state to up

R2(config-if)#ip address 192.168.1.1 255.255.255.0

R2(config-if)#

R2(config-if)#interface serial 2/0

R2(config-if)#ip address 10.0.0.2 255.255.255.252

R2(config-if)#no shut

R2(config-if)#

*Jul 13 10:35:16.503: %LINK-3-UPDOWN: Interface Serial2/0, changed state to up

R2(config-if)#

*Jul 13 10:35:17.511: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/0, changed state to up

R2(config-if)#

R2(config-if)#do ping 10.0.0.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:

.!!!!

Success rate is 80 percent (4/5), round-trip min/avg/max = 20/36/64 ms

R2(config-if)#

R2(config-if)#interface serial 2/1

R2(config-if)#ip address 172.16.0.2 255.255.255.252

R2(config-if)#no shut

R2(config-if)#

*Jul 13 10:35:47.583: %LINK-3-UPDOWN: Interface Serial2/1, changed state to up

R2(config-if)#

*Jul 13 10:35:48.591: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/1, changed state to up

R2(config-if)#end

R2#

R3#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R3(config)#interface loop 0

R3(config-if)#

*Jul 13 10:36:34.551: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up

R3(config-if)#ip address 172.16.1.1 255.255.255.0

R3(config-if)#

R3(config-if)#interface serial 2/1

R3(config-if)#ip address 172.16.0.1 255.255.255.252

R3(config-if)#no shut

R3(config-if)#

*Jul 13 10:37:12.879: %LINK-3-UPDOWN: Interface Serial2/1, changed state to up

R3(config-if)#

*Jul 13 10:37:13.887: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/1, changed state to up

R3(config-if)#

R3(config-if)#do ping 172.16.0.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.0.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/16/20 ms

R3(config-if)#end

R3#

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#router bgp ?

<1-4294967295> Autonomous system number

<1.0-XX.YY> Autonomous system number

R1(config)#router bgp 200

R1(config-router)#?

Router configuration commands:

address-family Enter Address Family command mode

aggregate-address Configure BGP aggregate entries

auto-summary Enable automatic network number summarization

bgp BGP specific commands

default Set a command to its defaults

default-information Control distribution of default information

default-metric Set metric of redistributed routes

distance Define an administrative distance

distribute-list Filter networks in routing updates

exit Exit from routing protocol configuration mode

help Description of the interactive help system

maximum-paths Forward packets over multiple paths

neighbor Specify a neighbor router

network Specify a network to announce via BGP

no Negate a command or set its defaults

redistribute Redistribute information from another routing protocol

route-server-context Enter route server context command mode

scope Enter scope command mode

snmp Modify snmp parameters

synchronization Perform IGP synchronization

table-map Map external entry attributes into routing table

template Enter template command mode

timers Adjust routing timers

R1(config-router)#neighbor ?

A.B.C.D Neighbor address

WORD Neighbor tag

X:X:X:X::X Neighbor IPv6 address

R1(config-router)#neighbor 10.0.0.2 ?

activate Enable the Address Family for this Neighbor

advertise Advertise to this neighbor

advertise-map specify route-map for conditional advertisement

advertisement-interval Minimum interval between sending BGP routing updates

allowas-in Accept as-path with my AS present in it

capability Advertise capability to the peer

default-originate Originate default route to this neighbor

description Neighbor specific description

disable-connected-check one-hop away EBGP peer using loopback address

distribute-list Filter updates to/from this neighbor

dmzlink-bw Propagate the DMZ link bandwidth

ebgp-multihop Allow EBGP neighbors not on directly connected

networks

fall-over session fall on peer route lost

filter-list Establish BGP filters

ha-mode high availability mode

inherit Inherit a template

local-as Specify a local-as number

maximum-prefix Maximum number of prefixes accepted from this peer

next-hop-self Disable the next hop calculation for this neighbor

next-hop-unchanged Propagate next hop unchanged for iBGP paths to this

neighbor

password Set a password

peer-group Member of the peer-group

prefix-list Filter updates to/from this neighbor

remote-as Specify a BGP neighbor

remove-private-as Remove private AS number from outbound updates

route-map Apply route map to neighbor

route-reflector-client Configure a neighbor as Route Reflector client

route-server-client Configure a neighbor as Route Server client

send-community Send Community attribute to this neighbor

send-label Send NLRI + MPLS Label to this peer

shutdown Administratively shut down this neighbor

slow-peer Configure slow-peer

soft-reconfiguration Per neighbor soft reconfiguration

soo Site-of-Origin extended community

timers BGP per neighbor timers

translate-update Translate Update to MBGP format

transport Transport options

ttl-security BGP ttl security check

unsuppress-map Route-map to selectively unsuppress suppressed

routes

update-source Source of routing updates

version Set the BGP version to match a neighbor

weight Set default weight for routes from this neighbor

R1(config-router)#neighbor 10.0.0.2 remote-as ?

<1-4294967295> AS of remote neighbor

<1.0-XX.YY> AS of remote neighbor

R1(config-router)#neighbor 10.0.0.2 remote-as 100 // CONFIGURE EBGP NEIGHBOR

R1(config-router)#network 10.1.1.0 mask ?

A.B.C.D Network mask

R1(config-router)#network 10.1.1.0 mask 255.255.255.0

R1(config-router)#end

R1#

*Jul 13 10:41:55.611: %BGP-5-ADJCHANGE: neighbor 10.0.0.2 Up

R3#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R3(config)#router bgp 300

R3(config-router)#neighbor 172.16.0.2 remote-as 100

R3(config-router)#network 172.16.1.0 mask 255.255.255.0

R3(config-router)#end

R3#

*Jul 13 10:42:16.983: %BGP-5-ADJCHANGE: neighbor 172.16.0.2 Up

R2#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R2(config)#router bgp 100

R2(config-router)#neighbor 10.0.0.1 remote-as 200

R2(config-router)#

*Jul 13 10:41:54.911: %BGP-5-ADJCHANGE: neighbor 10.0.0.1 Up

R2(config-router)#

R2(config-router)#neighbor 172.16.0.1 remote-as 300

R2(config-router)#

*Jul 13 10:42:16.603: %BGP-5-ADJCHANGE: neighbor 172.16.0.1 Up

R2(config-router)#

R2(config-router)#network 192.168.0.0

R2(config-router)#network 192.168.1.0

R2(config-router)#end

R2#

R2#show ip route // VERIFY BGP ROUTES FROM ISP1 AND ISP2

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.2/32 is directly connected, Serial2/0

B 10.1.1.0/24 [20/0] via 10.0.0.1, 00:01:46

172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.2/32 is directly connected, Serial2/1

B 172.16.1.0/24 [20/0] via 172.16.0.1, 00:01:26

192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.0.0/24 is directly connected, Loopback0

L 192.168.0.1/32 is directly connected, Loopback0

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.1.0/24 is directly connected, Loopback1

L 192.168.1.1/32 is directly connected, Loopback1

R2#tclsh

R2(tcl)#foreach address {

+>(tcl)#10.0.0.1

+>(tcl)#10.0.0.2

+>(tcl)#10.1.1.1

+>(tcl)#172.16.0.1

+>(tcl)#172.16.0.2

+>(tcl)#172.16.1.1

+>(tcl)#192.168.0.1

+>(tcl)#192.168.1.1

+>(tcl)#} {

+>(tcl)#ping $address }

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 20/28/52 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.0.0.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 32/36/40 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/14/20 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.0.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 8/13/16 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.0.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 16/26/40 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/18/24 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.0.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

R2#show ip bgp // VERIFY BGP TABLE

BGP table version is 5, local router ID is 192.168.1.1 // LOCAL-ID IS THE HIGHEST LOOPBACK IP

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path

*> 10.1.1.0/24 10.0.0.1 0 0 200 i

*> 172.16.1.0/24 172.16.0.1 0 0 300 i

*> 192.168.0.0 0.0.0.0 0 32768 i

*> 192.168.1.0 0.0.0.0 0 32768 i

R1#show ip bgp

BGP table version is 5, local router ID is 10.1.1.1 // NOTICE BGP TABLE VERSION IS ALSO 5

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path

*> 10.1.1.0/24 0.0.0.0 0 32768 i

*> 172.16.1.0/24 10.0.0.2 0 100 300 i

*> 192.168.0.0 10.0.0.2 0 0 100 i

*> 192.168.1.0 10.0.0.2 0 0 100 i

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#interface loop 0

R1(config-if)#shut

R1(config-if)#

*Jul 13 10:47:59.903: %LINK-5-CHANGED: Interface Loopback0, changed state to administratively down

*Jul 13 10:48:00.903: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to down

R2#show ip bgp

BGP table version is 6, local router ID is 192.168.1.1 // BGP TABLE INCREMENTED TO 6 SINCE ISP1 NETWORK 10.1.1.0/24 WAS REMOVED IN THE BGP TABLE

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path

*> 172.16.1.0/24 172.16.0.1 0 0 300 i

*> 192.168.0.0 0.0.0.0 0 32768 i

*> 192.168.1.0 0.0.0.0 0 32768 i

R1(config)#interface loop 0

R1(config-if)#no shut

R1(config-if)#

*Jul 13 10:49:16.295: %LINK-3-UPDOWN: Interface Loopback0, changed state to up

*Jul 13 10:49:17.295: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up

R1#show ip bgp

BGP table version is 7, local router ID is 10.1.1.1 // BGP TABLE VERSION INCREMENTED AGAIN

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path

*> 10.1.1.0/24 0.0.0.0 0 32768 i

*> 172.16.1.0/24 10.0.0.2 0 100 300 i

*> 192.168.0.0 10.0.0.2 0 0 100 i

*> 192.168.1.0 10.0.0.2 0 0 100 i

R2#show ip bgp

BGP table version is 7, local router ID is 192.168.1.1

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path

*> 10.1.1.0/24 10.0.0.1 0 0 200 i

*> 172.16.1.0/24 172.16.0.1 0 0 300 i

*> 192.168.0.0 0.0.0.0 0 32768 i

*> 192.168.1.0 0.0.0.0 0 32768 i

R2#show ip bgp ?

A.B.C.D Network in the BGP routing table to display

A.B.C.D/nn IP prefix <network>/<length>, e.g., 35.0.0.0/8

all All address families

cidr-only Display only routes with non-natural netmasks

community Display routes matching the communities

community-list Display routes matching the community-list

dampening Display detailed information about dampening

extcommunity-list Display routes matching the extcommunity-list

filter-list Display routes conforming to the filter-list

import Display route topology import / export activity

inconsistency Display all inconsistent paths

inconsistent-as Display only routes with inconsistent origin ASs

injected-paths Display all injected paths

ipv4 Address family

ipv6 Address family

l2vpn Address family

labels Display Labels for IPv4 NLRI specific information

neighbors Detailed information on TCP and BGP neighbor connections

nexthops Nexthop address table

nsap Address family

oer-paths Display all oer controlled paths

paths Path information

peer-group Display information on peer-groups

pending-prefixes Display prefixes pending deletion

prefix-list Display routes matching the prefix-list

quote-regexp Display routes matching the AS path "regular expression"

regexp Display routes matching the AS path regular expression

replication Display replication status of update-group(s)

rib-failure Display bgp routes that failed to install in the routing

table (RIB)

route-map Display routes matching the route-map

route-server Route server information

rpki Display RPKI Neighbor Cache

rtfilter Address family

summary Summary of BGP neighbor status

template Display peer-policy/peer-session templates

topology Routing topology instance

update-group Display information on update-groups

update-sources Update source interface table

va Display virtual aggregation prefixes

version Display prefixes with matching version numbers

vpnv4 Address family

vpnv6 Address family

| Output modifiers

<cr>

R2#show ip bgp neighbors

BGP neighbor is 10.0.0.1, remote AS 200, external link

BGP version 4, remote router ID 10.1.1.1

BGP state = Established, up for 00:08:43 // ESTABLISHED BGP STATE IS GOOD AND NOTICE UPTIME

Last read 00:00:22, last write 00:00:30, hold time is 180, keepalive interval is 60 seconds

Neighbor sessions:

1 active, is not multisession capable (disabled)

Neighbor capabilities:

Route refresh: advertised and received(new)

Four-octets ASN Capability: advertised and received

Address family IPv4 Unicast: advertised and received

Enhanced Refresh Capability: advertised and received

Multisession Capability:

Stateful switchover support enabled: NO for session 1

Message statistics:

InQ depth is 0

OutQ depth is 0

Sent Rcvd

Opens: 1 1

Notifications: 0 0

Updates: 5 4

Keepalives: 9 10

Route Refresh: 0 0

Total: 15 15

Default minimum time between advertisement runs is 30 seconds

For address family: IPv4 Unicast

Session: 10.0.0.1

BGP table version 7, neighbor version 7/0

Output queue size : 0

Index 1, Advertise bit 0

1 update-group member

Slow-peer detection is disabled

Slow-peer split-update-group dynamic is disabled

Sent Rcvd

Prefix activity: ---- ----

Prefixes Current: 4 1 (Consumes 64 bytes)

Prefixes Total: 5 2

Implicit Withdraw: 0 0

Explicit Withdraw: 1 1

Used as bestpath: n/a 1

Used as multipath: n/a 0

Outbound Inbound

Local Policy Denied Prefixes: -------- -------

Bestpath from this peer: 1 n/a

Invalid Path: 1 n/a

Total: 2 0

Number of NLRIs in the update sent: max 2, min 0

Last detected as dynamic slow peer: never

Dynamic slow peer recovered: never

Refresh Epoch: 1

Last Sent Refresh Start-of-rib: never

Last Sent Refresh End-of-rib: never

Last Received Refresh Start-of-rib: never

Last Received Refresh End-of-rib: never

Sent Rcvd

Refresh activity: ---- ----

Refresh Start-of-RIB 0 0

Refresh End-of-RIB 0 0

Address tracking is enabled, the RIB does have a route to 10.0.0.1

Connections established 1; dropped 0

Last reset never

Transport(tcp) path-mtu-discovery is enabled

Graceful-Restart is disabled

Connection state is ESTAB, I/O status: 1, unread input bytes: 0

Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 1

Local host: 10.0.0.2, Local port: 59509

Foreign host: 10.0.0.1, Foreign port: 179

Connection tableid (VRF): 0

Maximum output segment queue size: 50

Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)

Event Timers (current time is 0x129728):

Timer Starts Wakeups Next

Retrans 15 0 0x0

TimeWait 0 0 0x0

AckHold 13 8 0x0

SendWnd 0 0 0x0

KeepAlive 0 0 0x0

GiveUp 0 0 0x0

PmtuAger 1 0 0x13C300

DeadWait 0 0 0x0

Linger 0 0 0x0

ProcessQ 0 0 0x0

iss: 3629964154 snduna: 3629964593 sndnxt: 3629964593

irs: 2070890835 rcvnxt: 2070891241

sndwnd: 15946 scale: 0 maxrcvwnd: 16384

rcvwnd: 15979 scale: 0 delrcvwnd: 405

SRTT: 865 ms, RTTO: 1866 ms, RTV: 1001 ms, KRTT: 0 ms

minRTT: 8 ms, maxRTT: 1000 ms, ACK hold: 200 ms

Status Flags: active open

Option Flags: nagle, path mtu capable

IP Precedence value : 6

Datagrams (max data segment is 1460 bytes):

Rcvd: 28 (out of order: 0), with data: 14, total data bytes: 405

Sent: 27 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 15, total data bytes: 438

Packets received in fast path: 0, fast processed: 0, slow path: 0

fast lock acquisition failures: 0, slow path: 0

TCP Semaphore 0x6A3C13B0 FREE

BGP neighbor is 172.16.0.1, remote AS 300, external link

BGP version 4, remote router ID 172.16.1.1

BGP state = Established, up for 00:08:21

Last read 00:00:41, last write 00:00:22, hold time is 180, keepalive interval is 60 seconds

Neighbor sessions:

1 active, is not multisession capable (disabled)

Neighbor capabilities:

Route refresh: advertised and received(new)

Four-octets ASN Capability: advertised and received

Address family IPv4 Unicast: advertised and received

Enhanced Refresh Capability: advertised and received

Multisession Capability:

Stateful switchover support enabled: NO for session 1

Message statistics:

InQ depth is 0

OutQ depth is 0

Sent Rcvd

Opens: 1 1

Notifications: 0 0

Updates: 6 2

Keepalives: 9 10

Route Refresh: 0 0

Total: 18 13

Default minimum time between advertisement runs is 30 seconds

For address family: IPv4 Unicast

Session: 172.16.0.1

BGP table version 7, neighbor version 7/0

Output queue size : 0

Index 1, Advertise bit 0

1 update-group member

Slow-peer detection is disabled

Slow-peer split-update-group dynamic is disabled

Sent Rcvd

Prefix activity: ---- ----

Prefixes Current: 4 1 (Consumes 64 bytes)

Prefixes Total: 5 1

Implicit Withdraw: 0 0

Explicit Withdraw: 1 0

Used as bestpath: n/a 1

Used as multipath: n/a 0

Outbound Inbound

Local Policy Denied Prefixes: -------- -------

Bestpath from this peer: 1 n/a

Invalid Path: 1 n/a

Total: 2 0

Number of NLRIs in the update sent: max 2, min 0

Last detected as dynamic slow peer: never

Dynamic slow peer recovered: never

Refresh Epoch: 1

Last Sent Refresh Start-of-rib: 00:08:21

Last Sent Refresh End-of-rib: 00:08:21

Refresh-Out took 0 seconds

Last Received Refresh Start-of-rib: never

Last Received Refresh End-of-rib: never

Sent Rcvd

Refresh activity: ---- ----

Refresh Start-of-RIB 1 0

Refresh End-of-RIB 1 0

Address tracking is enabled, the RIB does have a route to 172.16.0.1

Connections established 1; dropped 0

Last reset never

Transport(tcp) path-mtu-discovery is enabled

Graceful-Restart is disabled

Connection state is ESTAB, I/O status: 1, unread input bytes: 0

Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 1

Local host: 172.16.0.2, Local port: 179

Foreign host: 172.16.0.1, Foreign port: 56007

Connection tableid (VRF): 0

Maximum output segment queue size: 50

Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)

Event Timers (current time is 0x12972C):

Timer Starts Wakeups Next

Retrans 14 0 0x0

TimeWait 0 0 0x0

AckHold 11 8 0x0

SendWnd 0 0 0x0

KeepAlive 0 0 0x0

GiveUp 0 0 0x0

PmtuAger 0 0 0x0

DeadWait 0 0 0x0

Linger 0 0 0x0

ProcessQ 0 0 0x0

iss: 505751287 snduna: 505751823 sndnxt: 505751823

irs: 3618503986 rcvnxt: 3618504311

sndwnd: 15849 scale: 0 maxrcvwnd: 16384

rcvwnd: 16060 scale: 0 delrcvwnd: 324

SRTT: 846 ms, RTTO: 1975 ms, RTV: 1129 ms, KRTT: 0 ms

minRTT: 16 ms, maxRTT: 1000 ms, ACK hold: 200 ms

Status Flags: passive open, gen tcbs

Option Flags: nagle, path mtu capable

IP Precedence value : 6

Datagrams (max data segment is 1460 bytes):

Rcvd: 27 (out of order: 0), with data: 12, total data bytes: 324

Sent: 27 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 16, total data bytes: 535

Packets received in fast path: 0, fast processed: 0, slow path: 0

fast lock acquisition failures: 0, slow path: 0

TCP Semaphore 0x6A3C12D0 FREE

R3#show ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is not set

10.0.0.0/24 is subnetted, 1 subnets

B 10.1.1.0 [20/0] via 172.16.0.2, 00:04:00 // ISP1 NETWORK

172.16.0.0/16 is variably subnetted, 4 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.1/32 is directly connected, Serial2/1

C 172.16.1.0/24 is directly connected, Loopback0

L 172.16.1.1/32 is directly connected, Loopback0

B 192.168.0.0/24 [20/0] via 172.16.0.2, 00:10:20

B 192.168.1.0/24 [20/0] via 172.16.0.2, 00:10:20

R3#traceroute 10.1.1.1 // TRACEROUTE FAILS SINCE ISP1 DON'T HAVE A ROUTE TO 172.16.0.0/30

Type escape sequence to abort.

Tracing the route to 10.1.1.1

VRF info: (vrf in name/id, vrf out name/id)

1 172.16.0.2 20 msec 16 msec 20 msec

2 * * *

3 * * *

4 *

R3#traceroute 10.1.1.1 source 172.16.1.1 // ISP2 TRANSITS VIA R2 TO REACH 10.1.1.0/24

Type escape sequence to abort.

Tracing the route to 10.1.1.1

VRF info: (vrf in name/id, vrf out name/id)

1 172.16.0.2 8 msec 20 msec 12 msec

2 10.0.0.1 16 msec 16 msec 20 msec

R1#show ip bgp     // ISP1 BGP TABLE DOESN'T HAVE 172.16.0.0/30
BGP table version is 5, local router ID is 10.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
*> 10.1.1.0/24      0.0.0.0                  0         32768 i
*> 172.16.1.0/24    10.0.0.2                               0 100 300 i
*> 192.168.0.0      10.0.0.2                 0             0 100 i
*> 192.168.1.0      10.0.0.2                 0             0 100 i

R2#conf t // CONFIGURE R2 TO ONLY ADVERTISE NETWORKS IN OWN AS

Enter configuration commands, one per line. End with CNTL/Z.

R2(config)#access-list 1 permit 192.168.0.0 0.0.1.255

R2(config)#

R2(config)#router bgp 100

R2(config-router)#neighbor 10.0.0.1 ?

activate Enable the Address Family for this Neighbor

advertise Advertise to this neighbor

advertise-map specify route-map for conditional advertisement

advertisement-interval Minimum interval between sending BGP routing updates

allowas-in Accept as-path with my AS present in it

capability Advertise capability to the peer

default-originate Originate default route to this neighbor

description Neighbor specific description

disable-connected-check one-hop away EBGP peer using loopback address

distribute-list Filter updates to/from this neighbor

dmzlink-bw Propagate the DMZ link bandwidth

ebgp-multihop Allow EBGP neighbors not on directly connected

networks

fall-over session fall on peer route lost

filter-list Establish BGP filters

ha-mode high availability mode

inherit Inherit a template

local-as Specify a local-as number

maximum-prefix Maximum number of prefixes accepted from this peer

next-hop-self Disable the next hop calculation for this neighbor

next-hop-unchanged Propagate next hop unchanged for iBGP paths to this

neighbor

password Set a password

peer-group Member of the peer-group

prefix-list Filter updates to/from this neighbor

remote-as Specify a BGP neighbor

remove-private-as Remove private AS number from outbound updates

route-map Apply route map to neighbor

route-reflector-client Configure a neighbor as Route Reflector client

route-server-client Configure a neighbor as Route Server client

send-community Send Community attribute to this neighbor

send-label Send NLRI + MPLS Label to this peer

shutdown Administratively shut down this neighbor

slow-peer Configure slow-peer

soft-reconfiguration Per neighbor soft reconfiguration

soo Site-of-Origin extended community

timers BGP per neighbor timers

translate-update Translate Update to MBGP format

transport Transport options

ttl-security BGP ttl security check

unsuppress-map Route-map to selectively unsuppress suppressed

routes

update-source Source of routing updates

version Set the BGP version to match a neighbor

weight Set default weight for routes from this neighbor

R2(config-router)#neighbor 10.0.0.1 distribute-list ?

<1-199> IP access list number

<1300-2699> IP access list number (expanded range)

WORD IP Access-list name

R2(config-router)#neighbor 10.0.0.1 distribute-list 1 ?

in Filter incoming updates

out Filter outgoing updates

R2(config-router)#neighbor 10.0.0.1 distribute-list 1 out

R2(config-router)#neighbor 172.16.0.1 distribute-list 1 out

R2(config-router)#end

R2#

R3#show ip route // NO ISP1 BGP NETWORK

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is not set

172.16.0.0/16 is variably subnetted, 4 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.1/32 is directly connected, Serial2/1

C 172.16.1.0/24 is directly connected, Loopback0

L 172.16.1.1/32 is directly connected, Loopback0

B 192.168.0.0/24 [20/0] via 172.16.0.2, 00:23:11

B 192.168.1.0/24 [20/0] via 172.16.0.2, 00:23:11

R1#show ip route // NO ISP2 BGP NETWORK

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 4 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.1/32 is directly connected, Serial2/0

C 10.1.1.0/24 is directly connected, Loopback0

L 10.1.1.1/32 is directly connected, Loopback0

B 192.168.0.0/24 [20/0] via 10.0.0.2, 00:23:42

B 192.168.1.0/24 [20/0] via 10.0.0.2, 00:23:42

R2#show ip route // CONFIGURE PRIMARY AND SECONDARY ISP DEFAULT ROUTE

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.2/32 is directly connected, Serial2/0

B 10.1.1.0/24 [20/0] via 10.0.0.1, 00:18:25

172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.2/32 is directly connected, Serial2/1

B 172.16.1.0/24 [20/0] via 172.16.0.1, 00:25:25

192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.0.0/24 is directly connected, Loopback0

L 192.168.0.1/32 is directly connected, Loopback0

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.1.0/24 is directly connected, Loopback1

L 192.168.1.1/32 is directly connected, Loopback1

R2#

R2#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R2(config)#ip route 0.0.0.0 0.0.0.0 10.0.0.1 ?

<1-255> Distance metric for this route

multicast multicast route

name Specify name of the next hop

permanent permanent route

tag Set tag for this route

track Install route depending on tracked item

<cr>

R2(config)#ip route 0.0.0.0 0.0.0.0 10.0.0.1 210 // PRIMARY DEFAULT STATIC ROUTE

R2(config)#ip route 0.0.0.0 0.0.0.0 172.16.0.1 220 // SECONDARY FLOATING STATIC ROUTE

R2(config)#end

R2#

*Jul 13 11:08:45.503: %SYS-5-CONFIG_I: Configured from console by console

R2#

R2#show ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is 10.0.0.1 to network 0.0.0.0

S* 0.0.0.0/0 [210/0] via 10.0.0.1

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.2/32 is directly connected, Serial2/0

B 10.1.1.0/24 [20/0] via 10.0.0.1, 00:19:34

172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.2/32 is directly connected, Serial2/1

B 172.16.1.0/24 [20/0] via 172.16.0.1, 00:26:34

192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.0.0/24 is directly connected, Loopback0

L 192.168.0.1/32 is directly connected, Loopback0

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.1.0/24 is directly connected, Loopback1

L 192.168.1.1/32 is directly connected, Loopback1

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#interface loop 100

R1(config-if)#

*Jul 13 11:09:52.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback100, changed state to up

R1(config-if)#ip address 192.168.100.1 255.255.255.0

R2#show ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is 10.0.0.1 to network 0.0.0.0

S* 0.0.0.0/0 [210/0] via 10.0.0.1

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.2/32 is directly connected, Serial2/0

B 10.1.1.0/24 [20/0] via 10.0.0.1, 00:21:12

172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.2/32 is directly connected, Serial2/1

B 172.16.1.0/24 [20/0] via 172.16.0.1, 00:28:12

192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.0.0/24 is directly connected, Loopback0

L 192.168.0.1/32 is directly connected, Loopback0

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.1.0/24 is directly connected, Loopback1

L 192.168.1.1/32 is directly connected, Loopback1

R2#ping 192.168.100.1 source 192.168.1.1 // PING WORKS VIA ISP1 DEFAULT ROUTE

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.100.1, timeout is 2 seconds:

Packet sent with a source address of 192.168.1.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/18/24 ms

R2#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R2(config)#no ip route 0.0.0.0 0.0.0.0 10.0.0.1 210

R2(config)#no ip route 0.0.0.0 0.0.0.0 172.16.0.1 220

R2(config)#end

R2#

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#router bgp 200

R1(config-router)#neighbor 10.0.0.2 ?

activate Enable the Address Family for this Neighbor

advertise Advertise to this neighbor

advertise-map specify route-map for conditional advertisement

advertisement-interval Minimum interval between sending BGP routing updates

allowas-in Accept as-path with my AS present in it

capability Advertise capability to the peer

default-originate Originate default route to this neighbor

description Neighbor specific description

disable-connected-check one-hop away EBGP peer using loopback address

distribute-list Filter updates to/from this neighbor

dmzlink-bw Propagate the DMZ link bandwidth

ebgp-multihop Allow EBGP neighbors not on directly connected

networks

fall-over session fall on peer route lost

filter-list Establish BGP filters

ha-mode high availability mode

inherit Inherit a template

local-as Specify a local-as number

maximum-prefix Maximum number of prefixes accepted from this peer

next-hop-self Disable the next hop calculation for this neighbor

next-hop-unchanged Propagate next hop unchanged for iBGP paths to this

neighbor

password Set a password

peer-group Member of the peer-group

prefix-list Filter updates to/from this neighbor

remote-as Specify a BGP neighbor

remove-private-as Remove private AS number from outbound updates

route-map Apply route map to neighbor

route-reflector-client Configure a neighbor as Route Reflector client

route-server-client Configure a neighbor as Route Server client

send-community Send Community attribute to this neighbor

send-label Send NLRI + MPLS Label to this peer

shutdown Administratively shut down this neighbor

slow-peer Configure slow-peer

soft-reconfiguration Per neighbor soft reconfiguration

soo Site-of-Origin extended community

timers BGP per neighbor timers

translate-update Translate Update to MBGP format

transport Transport options

ttl-security BGP ttl security check

unsuppress-map Route-map to selectively unsuppress suppressed

routes

update-source Source of routing updates

version Set the BGP version to match a neighbor

weight Set default weight for routes from this neighbor

R1(config-router)#neighbor 10.0.0.2 default-originate // PROPAGATE DEFAULT ROUTE VIA BGP

R2#show ip route // DEFAULT ROUTE NOT YET SHOWING

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.2/32 is directly connected, Serial2/0

B 10.1.1.0/24 [20/0] via 10.0.0.1, 00:24:15

172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.2/32 is directly connected, Serial2/1

B 172.16.1.0/24 [20/0] via 172.16.0.1, 00:31:15

192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.0.0/24 is directly connected, Loopback0

L 192.168.0.1/32 is directly connected, Loopback0

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.1.0/24 is directly connected, Loopback1

L 192.168.1.1/32 is directly connected, Loopback1

R1#clear ip bgp ? // FORCE BGP UPDATE

* Clear all peers

<1-4294967295> Clear peers with the AS number

<1.0-XX.YY> Clear peers with the AS number

A.B.C.D BGP neighbor address to clear

X:X:X:X::X BGP neighbor address to clear

all All address families

dampening Clear route flap dampening information

external Clear all external peers

flap-statistics Clear route flap statistics

internal Clear BGP internal statistics counters

ipv4 Address family

ipv6 Address family

l2vpn Address family

nsap Address family

peer-group Clear all members of peer-group

rtfilter Address family

sso SSO related

table-map Update BGP table-map configuration

topology Routing topology instance

update-group Clear all members of update-group

vpnv4 Address family

vpnv6 Address family

R1#clear ip bgp 10.0.0.2 // PREFER TO ISSUE clear ip bgp * <in | out> TO PERFORM BGP DATABASE SYNC WITHOUT DISRUPTING BGP ADJACENCY, MODERN IOS VERSION SUPPORTS BGP ROUTE REFRESH FEATURE

R1#

*Jul 13 11:13:57.907: %BGP-5-ADJCHANGE: neighbor 10.0.0.2 Down User reset

*Jul 13 11:13:57.911: %BGP_SESSION-5-ADJCHANGE: neighbor 10.0.0.2 IPv4 Unicast topology base removed from session User reset

*Jul 13 11:13:58.139: %BGP-5-ADJCHANGE: neighbor 10.0.0.2 Up

R2#

*Jul 13 11:13:57.223: %BGP-5-ADJCHANGE: neighbor 10.0.0.1 Down Peer closed the session

*Jul 13 11:13:57.223: %BGP_SESSION-5-ADJCHANGE: neighbor 10.0.0.1 IPv4 Unicast topology base removed from session Peer closed the session

*Jul 13 11:13:57.455: %BGP-5-ADJCHANGE: neighbor 10.0.0.1 Up

R2#

R2#show ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP

+ - replicated route, % - next hop override

Gateway of last resort is 10.0.0.1 to network 0.0.0.0

B* 0.0.0.0/0 [20/0] via 10.0.0.1, 00:00:09

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks

C 10.0.0.0/30 is directly connected, Serial2/0

L 10.0.0.2/32 is directly connected, Serial2/0

B 10.1.1.0/24 [20/0] via 10.0.0.1, 00:00:09

172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks

C 172.16.0.0/30 is directly connected, Serial2/1

L 172.16.0.2/32 is directly connected, Serial2/1

B 172.16.1.0/24 [20/0] via 172.16.0.1, 00:31:50

192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.0.0/24 is directly connected, Loopback0

L 192.168.0.1/32 is directly connected, Loopback0

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks

C 192.168.1.0/24 is directly connected, Loopback1

L 192.168.1.1/32 is directly connected, Loopback1

R2#ping 192.168.100.1 source 192.168.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.100.1, timeout is 2 seconds:

Packet sent with a source address of 192.168.1.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 20/28/52 ms

My Network Lab

Friday, February 8, 2019

Configuring BGP with Default Routing

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