doubt about if there is a limitant for number of interfaces that is passing traffic through a bgp session that is stablish by a loopback that is known from static routes
i have tested in GNS3 a bgp session from 2 routers that have 6 interfaces point to point and also have a static route to a loopback who is from the bgp session stablish, that is passing prefixes from side to side, and before this routers several routers that represent public address and when i test pings from side to side, i see traffic passing only for 4 of those interfaces, there is any limitant or some configuration that i am missing?
Topology
R2--------------------R1 (6 links p2p) R6--------------------R3
22.22.22.2 1.1.1.1 BGP 2.2.2.2 33.33.33.2
also
R4 R5
44.44.44.2 55.55.55.2
Configuration:
R1==================================
interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Loopback1
ip address 10.10.10.1 255.255.255.0
!
interface Loopback2
ip address 189.1.1.1 255.255.255.255
!
interface FastEthernet0/0
description TO_R6
ip address 40.40.40.1 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet0/1
description TO_R6
ip address 40.40.41.1 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet1/0
description TO_R6
ip address 40.40.42.1 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet2/0
description TO_R6
ip address 40.40.43.1 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet3/0
ip address 44.44.44.1 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet4/0
ip address 22.22.22.1 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet5/0
description TO_R6
ip address 40.40.44.1 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet6/0
description TO_R6
ip address 40.40.45.1 255.255.255.252
load-interval 30
duplex auto
speed auto
!
!
router bgp 11172
no synchronization
bgp log-neighbor-changes
redistribute connected
neighbor 2.2.2.2 remote-as 22272
neighbor 2.2.2.2 ebgp-multihop 2
neighbor 2.2.2.2 update-source Loopback0
no auto-summary
!
no ip http server
no ip http secure-server
ip classless
ip route 2.2.2.2 255.255.255.255 40.40.40.2
ip route 2.2.2.2 255.255.255.255 40.40.41.2
ip route 2.2.2.2 255.255.255.255 40.40.42.2
ip route 2.2.2.2 255.255.255.255 40.40.43.2
ip route 2.2.2.2 255.255.255.255 40.40.44.2
ip route 2.2.2.2 255.255.255.255 40.40.45.2
R6==================================
interface Loopback0
ip address 2.2.2.2 255.255.255.255
!
interface Loopback1
ip address 8.8.8.8 255.255.255.255
!
interface Loopback2
ip address 148.2.2.2 255.255.255.255
!
interface FastEthernet0/0
description TO_R1
ip address 40.40.40.2 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet0/1
description TO_R1
ip address 40.40.41.2 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet1/0
description TO_R1
ip address 40.40.42.2 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet2/0
description TO_R1
ip address 40.40.43.2 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet3/0
ip address 55.55.55.1 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet4/0
ip address 33.33.33.1 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet5/0
description TO_R1
ip address 40.40.44.2 255.255.255.252
load-interval 30
duplex auto
speed auto
!
interface FastEthernet6/0
description TO_R1
ip address 40.40.45.2 255.255.255.252
load-interval 30
duplex auto
speed auto
!
!
router bgp 22272
no synchronization
bgp log-neighbor-changes
redistribute connected
neighbor 1.1.1.1 remote-as 11172
neighbor 1.1.1.1 ebgp-multihop 2
neighbor 1.1.1.1 update-source Loopback0
no auto-summary
!
no ip http server
no ip http secure-server
ip classless
ip route 1.1.1.1 255.255.255.255 40.40.40.1
ip route 1.1.1.1 255.255.255.255 40.40.41.1
ip route 1.1.1.1 255.255.255.255 40.40.42.1
ip route 1.1.1.1 255.255.255.255 40.40.43.1
ip route 1.1.1.1 255.255.255.255 40.40.44.1
ip route 1.1.1.1 255.255.255.255 40.40.45.1
R2==================================
interface FastEthernet0/0
ip address 22.22.22.2 255.255.255.252
duplex auto
speed auto
!
!
!
ip route 0.0.0.0 0.0.0.0 22.22.22.1
R3==================================
!
interface FastEthernet0/0
ip address 33.33.33.2 255.255.255.252
duplex auto
speed auto
!
!
ip route 0.0.0.0 0.0.0.0 33.33.33.1
====================================================================
Verification from pings and traffic on interfaces
pings from 22.22.22.2 to 33.33.33.2 mtu 9000 and repeat 10000 both sides
pings from 44.44.44.2 to 55.55.55.2 mtu 9000 and repeat 10000 both sides
and the verification of traffic just in 4 interfaces:
R1#show int | in rate|Fast
FastEthernet0/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 1131000 bits/sec, 107 packets/sec
FastEthernet0/1 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 1614000 bits/sec, 149 packets/sec
30 second output rate 1687000 bits/sec, 159 packets/sec
FastEthernet1/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 2819000 bits/sec, 267 packets/sec
30 second output rate 1043000 bits/sec, 101 packets/sec
FastEthernet2/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 576000 bits/sec, 50 packets/sec
FastEthernet3/0 is up, line protocol is up --------------------R4
Queueing strategy: fifo
5 minute input rate 516000 bits/sec, 57 packets/sec
5 minute output rate 514000 bits/sec, 56 packets/sec
FastEthernet4/0 is up, line protocol is up --------------------R2
Queueing strategy: fifo
5 minute input rate 760000 bits/sec, 82 packets/sec
5 minute output rate 762000 bits/sec, 82 packets/sec
FastEthernet5/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
FastEthernet6/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
now same traffic but fa0/0 shutdown:
R1#show int | in rate|Fast
FastEthernet0/0 is administratively down, line protocol is down <--------------------shutdown
Queueing strategy: fifo
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
FastEthernet0/1 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 5000 bits/sec, 0 packets/sec
30 second output rate 1204000 bits/sec, 113 packets/sec
FastEthernet1/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 4000 bits/sec, 0 packets/sec
30 second output rate 1132000 bits/sec, 108 packets/sec
FastEthernet2/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 2356000 bits/sec, 213 packets/sec
30 second output rate 1235000 bits/sec, 106 packets/sec
FastEthernet3/0 is up, line protocol is up --------------------R4
Queueing strategy: fifo
5 minute input rate 1956000 bits/sec, 204 packets/sec
5 minute output rate 1955000 bits/sec, 203 packets/sec
FastEthernet4/0 is up, line protocol is up --------------------R2
Queueing strategy: fifo
5 minute input rate 2138000 bits/sec, 211 packets/sec
5 minute output rate 2139000 bits/sec, 211 packets/sec
FastEthernet5/0 is up, line protocol is up
Queueing strategy: fifo
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
FastEthernet6/0 is up, line protocol is up <-------------------- traffic on this interface
Queueing strategy: fifo
30 second input rate 2418000 bits/sec, 229 packets/sec
30 second output rate 1219000 bits/sec, 116 packets/sec
_______________________________
R1:
R1#show ip bgp summ
BGP router identifier 189.1.1.1, local AS number 11172
BGP table version is 20, main routing table version 20
15 network entries using 1755 bytes of memory
20 path entries using 1040 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 3191 total bytes of memory
BGP activity 16/1 prefixes, 22/2 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
2.2.2.2 4 22272 32 32 20 0 0 00:27:57 10
R1#show ip route 2.2.2.2
Routing entry for 2.2.2.2/32
Known via "static", distance 1, metric 0
Routing Descriptor Blocks:
* 40.40.45.2
Route metric is 0, traffic share count is 1
40.40.44.2
Route metric is 0, traffic share count is 1
40.40.43.2
Route metric is 0, traffic share count is 1
40.40.42.2
Route metric is 0, traffic share count is 1
40.40.41.2
Route metric is 0, traffic share count is 1
R1#show ip cef 2.2.2.2
2.2.2.2/32, version 55, epoch 0, per-destination sharing
0 packets, 0 bytes
via 40.40.45.2, 0 dependencies, recursive
traffic share 1
next hop 40.40.45.2, FastEthernet6/0 via 40.40.45.2/32
valid adjacency
via 40.40.44.2, 1 dependency, recursive
traffic share 1
next hop 40.40.44.2, FastEthernet5/0 via 40.40.44.2/32
valid adjacency
via 40.40.43.2, 1 dependency, recursive
traffic share 1
next hop 40.40.43.2, FastEthernet2/0 via 40.40.43.2/32
valid adjacency
via 40.40.42.2, 1 dependency, recursive
traffic share 1
next hop 40.40.42.2, FastEthernet1/0 via 40.40.42.2/32
valid adjacency
via 40.40.41.2, 1 dependency, recursive
traffic share 1
next hop 40.40.41.2, FastEthernet0/1 via 40.40.41.2/32
valid adjacency
0 packets, 0 bytes switched through the prefix
tmstats: external 0 packets, 0 bytes
internal 0 packets, 0 bytes
R6:
R6#show ip bgp summary
BGP router identifier 148.2.2.2, local AS number 22272
BGP table version is 19, main routing table version 19
15 network entries using 1755 bytes of memory
20 path entries using 1040 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 3191 total bytes of memory
BGP activity 16/1 prefixes, 22/2 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
1.1.1.1 4 11172 33 33 19 0 0 00:28:29 10
R6#show ip route 1.1.1.1
Routing entry for 1.1.1.1/32
Known via "static", distance 1, metric 0
Routing Descriptor Blocks:
* 40.40.45.1
Route metric is 0, traffic share count is 1
40.40.44.1
Route metric is 0, traffic share count is 1
40.40.43.1
Route metric is 0, traffic share count is 1
40.40.42.1
Route metric is 0, traffic share count is 1
40.40.41.1
Route metric is 0, traffic share count is 1
R6#show ip cef 1.1.1.1
1.1.1.1/32, version 51, epoch 0, per-destination sharing
0 packets, 0 bytes
via 40.40.45.1, 0 dependencies, recursive
traffic share 1
next hop 40.40.45.1, FastEthernet6/0 via 40.40.45.1/32
valid adjacency
via 40.40.44.1, 1 dependency, recursive
traffic share 1
next hop 40.40.44.1, FastEthernet5/0 via 40.40.44.1/32
valid adjacency
via 40.40.43.1, 1 dependency, recursive
traffic share 1
next hop 40.40.43.1, FastEthernet2/0 via 40.40.43.1/32
valid adjacency
via 40.40.42.1, 1 dependency, recursive
traffic share 1
next hop 40.40.42.1, FastEthernet1/0 via 40.40.42.1/32
valid adjacency
via 40.40.41.1, 1 dependency, recursive
traffic share 1
next hop 40.40.41.1, FastEthernet0/1 via 40.40.41.1/32
valid adjacency
0 packets, 0 bytes switched through the prefix
tmstats: external 0 packets, 0 bytes
internal 0 packets, 0 bytes
Best regards
