BGP using Layer 3 Switches

[Ranjita]

Hi All,
I have 2 networks connected via OSPF. I need to route the connected networks to a third network via BGP.

I noticed that BGP peering is established but no entry is visible on the routing table.

Below is an extract of BGP config:

router bgp 65200.10
bgp router-id 10.169.24.180
bgp asnotation dot
bgp log-neighbor-changes
network 10.169.30.128 mask 255.255.255.192
network 10.169.30.192 mask 255.255.255.224
network 10.169.30.224 mask 255.255.255.224
redistribute ospf 6
neighbor 10.169.24.177 remote-as 65200.16
neighbor 10.169.24.177 next-hop-self all

sh bgp neighbors 10.169.24.177 advertised-routes
% Command accepted but obsolete, unreleased or unsupported; see documentation.

BGP table version is 6, local router ID is 10.169.24.180
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,
t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path
*> 10.169.30.0/26 10.169.30.228 2 32768 ?
*> 10.169.30.64/26 10.169.30.228 2 32768 ?
*> 10.169.30.128/26 0.0.0.0 0 32768 i
*> 10.169.30.192/27 0.0.0.0 0 32768 i
*> 10.169.30.224/27 0.0.0.0 0 32768 i

Please advise on how this issue can be fixed.

Regards,

Ranjita

[Georg Pauwen]

Hello,

post a schematic drawing of your topology, showing how your routers are connected, as well as the full running configs of all routers involved.

[Martin L]

BGP on L3 switch?  how much RAM does  ur switch  have?  how much is free now? how much is used by BGP process ? what is CPU utilization ?

 Regards, ML
**Please Rate All Helpful Responses **

[M02@rt37 · Accepted solution]

Hello @Ranjita 

The output of that command sh bgp neighbors 10.169.24.177 received routes is empty ?

[Ranjita]

Hi,

Please check output below

sh bgp neighbors 10.169.24.177 received-routes
% Command accepted but obsolete, unreleased or unsupported; see documentation.

% Inbound soft reconfiguration not enabled on 10.169.24.177

[M02@rt37]

Thanks @Ranjita for these output.

Go to the neighbor host (10.169.24.177) and ensure that you redistribute/adverise something.

#sh bgp neighbors 10.169.24.182 advertised-routes

Thanks again.

[Ranjita]

Hi,

Output is as below:

Result of the command: "sh bgp neighbors 10.169.24.182 advertised-routes"

Total number of prefixes 0

[M02@rt37]

So @Ranjita 

Issue is advertisement from that router.

Check the redistribution, or network command. Ensure that what you want to advertise is installed in the RIB of that host.

[MHM Cisco World]

Show ip bgp neighbors summary 

Show tcp breif 

Share above 

MHM

[Ranjita]

Hi,

Thanks for the response.Please check output below:

sh ip bgp neighbors
BGP neighbor is 10.169.24.177, remote AS 65200.16, external link
BGP version 4, remote router ID 10.169.24.254
BGP state = Established, up for 16:58:18
Last read 00:00:59, last write 00:00:35, hold time is 180, keepalive interval is 60 seconds
Last update received: never
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
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: 3 0

X02YCA11UH001-KF001-SW#sh ip bgp neighbors br
^
% Invalid input detected at '^' marker.

X02YCA11UH001-KF001-SW#sh ip bgp neighbors
BGP neighbor is 10.169.24.177, remote AS 65200.16, external link
BGP version 4, remote router ID 10.169.24.254
BGP state = Established, up for 16:58:34
Last read 00:00:04, last write 00:00:51, hold time is 180, keepalive interval is 60 seconds
Last update received: never
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
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: 3 0
Keepalives: 1121 921
Route Refresh: 0 0
Total: 1125 922
Do log neighbor state changes (via global configuration)
Default minimum time between advertisement runs is 30 seconds

For address family: IPv4 Unicast
Session: 10.169.24.177
BGP table version 6, neighbor version 6/0
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: 5 0
Prefixes Total: 5 0
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 0
Used as multipath: n/a 0
Used as secondary: n/a 0

Outbound Inbound
Local Policy Denied Prefixes: -------- -------
Total: 0 0
Number of NLRIs in the update sent: max 3, 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 10.169.24.177
Route to peer address reachability Up: 1; Down: 0
Last notification 16:58:37
Connections established 1; dropped 0
Last reset never
External BGP neighbor configured for connected checks (single-hop no-disable-connected-check)
Interface associated: Vlan525 (peering address in same link)
Transport(tcp) path-mtu-discovery is enabled
Graceful-Restart is disabled
SSO 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: 10.169.24.182, Local port: 179
Foreign host: 10.169.24.177, Foreign port: 12711
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 0x1E97412E):
Timer Starts Wakeups Next
Retrans 1124 0 0x0
TimeWait 0 0 0x0
AckHold 922 902 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: 1007069267 snduna: 1007090772 sndnxt: 1007090772
irs: 2367823628 rcvnxt: 2367841181

sndwnd: 32768 scale: 0 maxrcvwnd: 16384
rcvwnd: 14940 scale: 0 delrcvwnd: 1444

SRTT: 1000 ms, RTTO: 1003 ms, RTV: 3 ms, KRTT: 0 ms
minRTT: 0 ms, maxRTT: 1000 ms, ACK hold: 200 ms
uptime: 61114820 ms, Sent idletime: 4126 ms, Receive idletime: 4326 ms
Status Flags: passive open, gen tcbs
Option Flags: nagle, path mtu capable
IP Precedence value : 6
Window update Optimisation : Disabled
ACK Optimisation : Disabled

Datagrams (max data segment is 1460 bytes):
Peer MSS: 1460
Rcvd: 2049 (out of order: 0), with data: 922, total data bytes: 17552
Sent: 2040 (retransmit: 0, fastretransmit: 0, partialack: 0, Second Congestion: 0), with data: 1123, total data bytes: 21504

Packets received in fast path: 0, fast processed: 0, slow path: 0
fast lock acquisition failures: 0, slow path: 0
TCP Semaphore 0x7F8A6711B8D0 FREE

sh tcp brief
TCB Local Address Foreign Address (state)
7F8A67015E20 10.169.24.182.179 10.169.24.177.12711 ESTAB

[MHM Cisco World · Accepted solution]

In Peer1

*> 10.169.30.0/26 10.169.30.228 2 32768 ? <-redistrubte via ospf
*> 10.169.30.64/26 10.169.30.228 2 32768 ? <- redistrubte via ospf

All below prefix is inject using network command 
*> 10.169.30.128/26 0.0.0.0 0 32768 i
*> 10.169.30.192/27 0.0.0.0 0 32768 i
*> 10.169.30.224/27 0.0.0.0 0 32768 i

In Peer2

Which if them is missing ?

MHM

[Ranjita]

Thanks for the reply. The neighbor was not advertising any routes to Peer 1 which is why the Perfix was 0.

I updated configuration on the other side and am able to receive the prefix now.

Thank you for the suggestion.