Sunday, March 1, 2015

BGP Route Reflectors and Route Filters

We've deployed BGP route reflectors globally in our enterprise. For each region (ours is APAC), we installed two Cisco ASR-1002X as BGP route reflectors (the other one for redundancy). These beefy routers can easily hold thousands of megabytes of public Internet routes. This also makes our IBGP config smaller and more scalable since it doesn't need a full mesh on all IBGP peers.

I did a route reflector lab for CCNP ROUTE. I got a bit intimated doing this lab since BGP isn't my strong point but while I was already doing the configuration, it's not so bad after all. It's just a matter of having a good solid BGP foundation (from my ISP job background) that I was able to pull this off.

 
SanJose1(config)#interface s0/0/0
SanJose1(config-if)#ip address 192.168.1.5 255.255.255.252
SanJose1(config-if)#clock rate 128000
SanJose1(config-if)#no shutdown
SanJose1(config-if)#
*Jan  3 15:34:53.515: %LINK-3-UPDOWN: Interface Serial0/0/0, changed state to down


SanJose2(config)#interface loopback0
SanJose2(config-if)#
*Jan  3 14:17:39.863: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up
SanJose2(config-if)#ip address 10.2.2.1 255.255.255.0
SanJose2(config-if)#interface s0/0/0
SanJose2(config-if)#ip address 192.168.1.6 255.255.255.252
SanJose2(config-if)#no shutdown
SanJose2(config-if)#
*Jan  3 14:18:14.847: %LINK-3-UPDOWN: Interface Serial0/0/0, changed state to up
*Jan  3 14:18:15.847: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0, changed state to up
SanJose2(config-if)#do ping 192.168.1.5

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/15/16 ms
SanJose2(config-if)#interface s0/0/1
SanJose2(config-if)#ip address 172.24.1.17 255.255.255.0
SanJose2(config-if)#clock rate 128000
SanJose2(config-if)#no shutdown
SanJose2(config-if)#
*Jan  3 14:18:44.299: %LINK-3-UPDOWN: Interface Serial0/0/1, changed state to up
*Jan  3 14:18:45.299: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1, changed state to up


SanJose3(config)#interface s0/0/1
SanJose3(config-if)#ip address 172.24.1.18 255.255.255.0
SanJose3(config-if)#no shutdown
SanJose3(config-if)#do ping 172.24.1.17

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.17, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms


SanJose1(config)#router rip
SanJose1(config-router)#version 2
SanJose1(config-router)#no auto-summary
SanJose1(config-router)#network 192.168.1.0


SanJose2(config)#router rip
SanJose2(config-router)#version 2
SanJose2(config-router)#no auto-summary
SanJose2(config-router)#network 172.24.0.0
SanJose2(config-router)#network 192.168.1.0
SanJose2(config-router)#network 10.0.0.0


SanJose3(config)#router rip
SanJose3(config-router)#version 2
SanJose3(config-router)#no auto-summary
SanJose3(config-router)#network 172.24.0.0


SanJose1#show ip route
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
R       172.24.1.0 [120/1] via 192.168.1.6, 00:00:06, Serial0/0/0
     10.0.0.0/24 is subnetted, 1 subnets
R       10.2.2.0 [120/1] via 192.168.1.6, 00:00:06, Serial0/0/0
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0


SanJose1#tclsh
SanJose1(tcl)#foreach address {
+>10.2.2.1
+>192.168.1.5
+>192.168.1.6
+>172.24.1.17
+>172.24.1.18
+>} {
+>ping $address }

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/32 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.17, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.18, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/32 ms


SanJose2(config)#router bgp 100
SanJose2(config-router)#neighbor 192.168.1.5 remote-as 100
SanJose2(config-router)#neighbor 172.24.1.18 remote-as 100


SanJose1(config)#router bgp 100
SanJose1(config-router)#neighbor 192.168.1.6 remote-as 100
SanJose1(config-router)#
*Jan  3 15:44:53.379: %BGP-5-ADJCHANGE: neighbor 192.168.1.6 Up


SanJose3(config)#router bgp 100
SanJose3(config-router)#neighbor 172.24.1.17 remote-as 100
SanJose3(config-router)#
*Jan  3 15:04:45.779: %BGP-5-ADJCHANGE: neighbor 172.24.1.17 Up


SanJose2#show ip bgp neighbors
BGP neighbor is 172.24.1.18,  remote AS 100, internal link  
  BGP version 4, remote router ID 172.24.1.18
  BGP state = Established, up for 00:00:52  
  Last read 00:00:52, last write 00:00:52, hold time is 180, keepalive interval is 60 seconds
  Neighbor capabilities:
    Route refresh: advertised and received(new)
    New ASN Capability: advertised and received
    Address family IPv4 Unicast: advertised and received
  Message statistics:
    InQ depth is 0
    OutQ depth is 0

                         Sent       Rcvd
    Opens:                  1          1
    Notifications:          0          0
    Updates:                0          0
    Keepalives:             1          1
    Route Refresh:          0          0
    Total:                  2          2
  Default minimum time between advertisement runs is 0 seconds

 For address family: IPv4 Unicast
  BGP table version 1, neighbor version 0/0
  Output queue size : 0
  Index 2, Offset 0, Mask 0x4
  2 update-group member
                                 Sent       Rcvd
  Prefix activity:               ----       ----
    Prefixes Current:               0          0
    Prefixes Total:                 0          0
    Implicit Withdraw:              0          0
    Explicit Withdraw:              0          0
    Used as bestpath:             n/a          0
    Used as multipath:            n/a          0

                                   Outbound    Inbound
  Local Policy Denied Prefixes:    --------    -------
    Total:                                0          0
  Number of NLRIs in the update sent: max 0, min 0

  Address tracking is enabled, the RIB does have a route to 172.24.1.18
  Connections established 1; dropped 0
  Last reset never
  Transport(tcp) path-mtu-discovery is enabled
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 255
Local host: 172.24.1.17, Local port: 179
Foreign host: 172.24.1.18, Foreign port: 14628
Connection tableid (VRF): 0

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

Event Timers (current time is 0x12422C):
Timer          Starts    Wakeups            Next
Retrans             4          0             0x0
TimeWait            0          0             0x0
AckHold             3          2             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: 1760080277  snduna: 1760080369  sndnxt: 1760080369     sndwnd:  16293
irs:  615136447  rcvnxt:  615136539  rcvwnd:      16293  delrcvwnd:     91

SRTT: 124 ms, RTTO: 1405 ms, RTV: 1281 ms, KRTT: 0 ms
minRTT: 8 ms, maxRTT: 300 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: 7 (out of order: 0), with data: 3, total data bytes: 91
Sent: 6 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 3, total

data bytes: 91
 Packets received in fast path: 0, fast processed: 0, slow path: 0
 fast lock acquisition failures: 0, slow path: 0

BGP neighbor is 192.168.1.5,  remote AS 100, internal link  
  BGP version 4, remote router ID 192.168.1.5
  BGP state = Established, up for 00:01:29   
  Last read 00:00:39, last write 00:00:31, hold time is 180, keepalive interval is 60 seconds
  Neighbor capabilities:
    Route refresh: advertised and received(new)
    New ASN Capability: advertised and received
    Address family IPv4 Unicast: advertised and received
  Message statistics:
    InQ depth is 0
    OutQ depth is 0

                         Sent       Rcvd
    Opens:                  1          1
    Notifications:          0          0
    Updates:                0          0
    Keepalives:             2          2
    Route Refresh:          0          0
    Total:                  3          3
  Default minimum time between advertisement runs is 0 seconds

 For address family: IPv4 Unicast
  BGP table version 1, neighbor version 1/0
  Output queue size : 0
  Index 2, Offset 0, Mask 0x4
  2 update-group member
                                 Sent       Rcvd
  Prefix activity:               ----       ----
    Prefixes Current:               0          0
    Prefixes Total:                 0          0
    Implicit Withdraw:              0          0
    Explicit Withdraw:              0          0
    Used as bestpath:             n/a          0
    Used as multipath:            n/a          0

                                   Outbound    Inbound
  Local Policy Denied Prefixes:    --------    -------
    Total:                                0          0
  Number of NLRIs in the update sent: max 0, min 0

  Address tracking is enabled, the RIB does have a route to 192.168.1.5
  Connections established 1; dropped 0
  Last reset never
  Transport(tcp) path-mtu-discovery is enabled
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 255
Local host: 192.168.1.6, Local port: 51613
Foreign host: 192.168.1.5, Foreign port: 179
Connection tableid (VRF): 0

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

Event Timers (current time is 0x1259B8):
Timer          Starts    Wakeups            Next
Retrans             4          0             0x0
TimeWait            0          0             0x0
AckHold             3          2             0x0
SendWnd             0          0             0x0
KeepAlive           0          0             0x0
GiveUp              0          0             0x0
PmtuAger            1          0        0x1A18C8
DeadWait            0          0             0x0
Linger              0          0             0x0
ProcessQ            0          0             0x0

iss:  235163843  snduna:  235163935  sndnxt:  235163935     sndwnd:  16293
irs:   61301986  rcvnxt:   61302078  rcvwnd:      16293  delrcvwnd:     91

SRTT: 124 ms, RTTO: 1405 ms, RTV: 1281 ms, KRTT: 0 ms
minRTT: 8 ms, maxRTT: 300 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: 6 (out of order: 0), with data: 3, total data bytes: 91
Sent: 7 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 3, total

data bytes: 91
 Packets received in fast path: 0, fast processed: 0, slow path: 0
 fast lock acquisition failures: 0, slow path: 0


SanJose3(config)#interface loopback0
SanJose3(config-if)#
*Jan  3 15:07:07.631: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up
SanJose3(config-if)#ip address 198.133.219.1 255.255.255.0
SanJose3(config-if)#exit
SanJose3(config)#router bgp 100
SanJose3(config-router)#network 198.133.219.0    // ADVERTISE LOOPBACK INTO BGP


SanJose2#show ip route
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
C       172.24.1.0 is directly connected, Serial0/0/1
     10.0.0.0/24 is subnetted, 1 subnets
C       10.2.2.0 is directly connected, Loopback0
B    198.133.219.0/24 [200/0] via 172.24.1.18, 00:00:33  
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0

SanJose2#ping 198.133.219.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.133.219.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms


SanJose1#show ip route   // SanJose1 ISN'T CONFIGURE FOR IBGP PEERING WITH SanJose3
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
R       172.24.1.0 [120/1] via 192.168.1.6, 00:00:11, Serial0/0/0
     10.0.0.0/24 is subnetted, 1 subnets
R       10.2.2.0 [120/1] via 192.168.1.6, 00:00:11, Serial0/0/0
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0


SanJose2(config)#router bgp 100
SanJose2(config-router)#neighbor 192.168.1.5 ?
  activate                 Enable the Address Family for 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
  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
  send-community           Send Community attribute to this neighbor
  send-label               Send NLRI + MPLS Label to this peer
  shutdown                 Administratively shut down this neighbor
  soft-reconfiguration     Per neighbor soft reconfiguration
  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

SanJose2(config-router)#neighbor 192.168.1.5 route-reflector-client   // CONFIGURE SanJose2 AS ROUTE

REFLECTOR TO ELIMINATE IBGP FULL MESH
SanJose2(config-router)#neighbor 192.168.1.5 route-reflector-client
*Jan  3 14:32:54.191: %BGP-5-ADJCHANGE: neighbor 192.168.1.5 Down RR client config change
*Jan  3 14:32:57.659: %BGP-5-ADJCHANGE: neighbor 192.168.1.5 Up
SanJose2(config-router)#neighbor 172.24.1.18 route-reflector-client
SanJose2(config-router)#
*Jan  3 14:33:12.391: %BGP-5-ADJCHANGE: neighbor 172.24.1.18 Down RR client config change
*Jan  3 14:33:15.067: %BGP-5-ADJCHANGE: neighbor 172.24.1.18 Up


SanJose2#show ip protocols
Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 18 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Redistributing: rip
  Default version control: send version 2, receive version 2
    Interface             Send  Recv  Triggered RIP  Key-chain
    Serial0/0/0           2     2
    Serial0/0/1           2     2
    Loopback0             2     2
  Automatic network summarization is not in effect
  Maximum path: 4
  Routing for Networks:
    10.0.0.0
    172.24.0.0
    192.168.1.0
  Routing Information Sources:
    Gateway         Distance      Last Update
  Distance: (default is 120)

Routing Protocol is "bgp 100"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Route Reflector for address family IPv4 Unicast, 2 clients  
  Route Reflector for address family IPv6 Unicast, 2 clients
  Route Reflector for address family IPv4 MDT, 2 clients
  Route Reflector for address family VPNv4 Unicast, 2 clients
  Route Reflector for address family VPNv6 Unicast, 2 clients
  Route Reflector for address family IPv4 Multicast, 2 clients
  Route Reflector for address family IPv6 Multicast, 2 clients
  Route Reflector for address family NSAP Unicast, 2 clients
  IGP synchronization is disabled
  Automatic route summarization is disabled
  Neighbor(s):
    Address          FiltIn FiltOut DistIn DistOut Weight RouteMap
    172.24.1.18
    192.168.1.5
  Maximum path: 1
  Routing Information Sources:
    Gateway         Distance      Last Update
    172.24.1.18          200      00:02:06
  Distance: external 20 internal 200 local 200


SanJose1#show ip protocols
Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 17 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Redistributing: rip
  Default version control: send version 2, receive version 2
    Interface             Send  Recv  Triggered RIP  Key-chain
    Serial0/0/0           2     2
  Automatic network summarization is not in effect
  Maximum path: 4
  Routing for Networks:
    192.168.1.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.1.6          120      00:00:00
  Distance: (default is 120)

Routing Protocol is "bgp 100"    // ROUTE REFLECTOR CLIENT IS UNAWARE OF BGP ROUTE REFLECTION
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  IGP synchronization is disabled
  Automatic route summarization is disabled
  Neighbor(s):
    Address          FiltIn FiltOut DistIn DistOut Weight RouteMap
    192.168.1.6
  Maximum path: 1
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.1.6          200      00:02:43
  Distance: external 20 internal 200 local 200


SanJose1#show ip route
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
R       172.24.1.0 [120/1] via 192.168.1.6, 00:00:05, Serial0/0/0
     10.0.0.0/24 is subnetted, 1 subnets
R       10.2.2.0 [120/1] via 192.168.1.6, 00:00:05, Serial0/0/0
B    198.133.219.0/24 [200/0] via 172.24.1.18, 00:03:45   // RECEIVED SanJose3 LOPPBACK0 SUBNET EVEN IF NOT AN IBGP PEER; RECEIVED FROM ROUTE REFLECTOR SanJose2
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0

SanJose1#ping 198.133.219.1   // CAN PING IP ADDRESS EVEN IF NEXT-HOP IP 172.24.1.18 ISN'T DIRECTLY CONNECTED

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.133.219.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/28 ms


SanJose3(config)#router bgp 100
SanJose3(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
  synchronization      Perform IGP synchronization
  table-map            Map external entry attributes into routing table
  template             Enter template command mode
  timers               Adjust routing timers

SanJose3(config-router)#aggregate-address ?
  A.B.C.D  Aggregate address

SanJose3(config-router)#aggregate-address 198.0.0.0 ?
  A.B.C.D  Aggregate mask

SanJose3(config-router)#aggregate-address 198.0.0.0 255.0.0.0


SanJose2#show ip bgp 198.0.0.0
BGP routing table entry for 198.0.0.0/8, version 5
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Flag: 0x820
  Advertised to update-groups:
        1
  Local, (aggregated by 100 172.24.1.18), (Received from a RR-client)  
    172.24.1.18 from 172.24.1.18 (172.24.1.18)
      Origin IGP, metric 0, localpref 100, valid, internal, atomic-aggregate, best  


SanJose1#show ip route   // SanJose2 REFLECTED SUPERNET ROUTE TO SanJose1
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
R       172.24.1.0 [120/1] via 192.168.1.6, 00:00:11, Serial0/0/0
     10.0.0.0/24 is subnetted, 1 subnets
R       10.2.2.0 [120/1] via 192.168.1.6, 00:00:11, Serial0/0/0
B    198.133.219.0/24 [200/0] via 172.24.1.18, 00:13:19  
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0
B    198.0.0.0/8 [200/0] via 172.24.1.18, 00:02:01   


SanJose2(config)#ip prefix-list ?
  WORD             Name of a prefix list
  sequence-number  Include/exclude sequence numbers in NVGEN

SanJose2(config)#ip prefix-list SUPERNET_ONLY ?
  deny         Specify packets to reject
  description  Prefix-list specific description
  permit       Specify packets to forward
  seq          sequence number of an entry

SanJose2(config)#ip prefix-list SUPERNET_ONLY permit ?
  A.B.C.D/nn  IP prefix <network>/<length>, e.g., 35.0.0.0/8

SanJose2(config)#ip prefix-list SUPERNET_ONLY permit 198.0.0.0/8
SanJose2(config)#router bgp 100
SanJose2(config-router)#neighbor 192.168.1.5 ?
  activate                 Enable the Address Family for 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
  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
  send-community           Send Community attribute to this neighbor
  send-label               Send NLRI + MPLS Label to this peer
  shutdown                 Administratively shut down this neighbor
  soft-reconfiguration     Per neighbor soft reconfiguration
  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

SanJose2(config-router)#neighbor 192.168.1.5 prefix-list ?
  WORD  Name of a prefix list

SanJose2(config-router)#neighbor 192.168.1.5 prefix-list SUPERNET_ONLY ?
  in   Filter incoming updates
  out  Filter outgoing updates

SanJose2(config-router)#neighbor 192.168.1.5 prefix-list SUPERNET_ONLY out   // PREVENT
198.133.219.0/24 ROUTE TO REFLECT ON SanJose1


SanJose1#show ip route
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
R       172.24.1.0 [120/1] via 192.168.1.6, 00:00:09, Serial0/0/0
     10.0.0.0/24 is subnetted, 1 subnets
R       10.2.2.0 [120/1] via 192.168.1.6, 00:00:09, Serial0/0/0
B    198.133.219.0/24 [200/0] via 172.24.1.18, 00:15:58
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0
B    198.0.0.0/8 [200/0] via 172.24.1.18, 00:04:40
SanJose1#clear ip bgp * soft
SanJose1#show ip route
Codes: 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

Gateway of last resort is not set

     172.24.0.0/24 is subnetted, 1 subnets
R       172.24.1.0 [120/1] via 192.168.1.6, 00:00:07, Serial0/0/0
     10.0.0.0/24 is subnetted, 1 subnets
R       10.2.2.0 [120/1] via 192.168.1.6, 00:00:07, Serial0/0/0
     192.168.1.0/30 is subnetted, 1 subnets
C       192.168.1.4 is directly connected, Serial0/0/0
B    198.0.0.0/8 [200/0] via 172.24.1.18, 00:05:05  

SanJose1#tclsh
SanJose1(tcl)#foreach address {
+>10.2.2.1
+>198.133.219.1
+>192.168.1.5
+>192.168.1.6
+>172.24.1.17
+>172.24.1.18
+>} {
+>ping $address }

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.133.219.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/28 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/32 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.17, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/15/16 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.18, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/31/44 ms

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