BGP state of down sessions is only IDLE (I don't see Active-state)...

kozorezdi · ‎01-27-2010

Hello everybody,

Down BGP sessions stay in only IDLE state by command : sh ip bgp summary. The router knows the path to the neighbor. For example:

80.81.192.A 4 2528B 0 0 0 0 0 01:31:26 Idle

#ping 80.81.192.A

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 80.81.192.202, timeout is 2 seconds:
!!!!! Success rate is 100 percent (5/5)

I don't see them as Active and it is strange to me...
Could you explain it?

#sh ver
Cisco IOS Software, c7600s72033_rp Software (c7600s72033_rp-ADVIPSERVICES-M), Version 12.2(33)SRD1, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Tue 24-Feb-09 23:34 by prod_rel_team

ROM: System Bootstrap, Version 12.2(17r)S4, RELEASE SOFTWARE (fc1)
BOOTLDR: Cisco IOS Software, c7600s72033_rp Software (c7600s72033_rp-ADVIPSERVICES-M), Version 12.2(33)SRD1, RELEASE SOFTWARE (fc4)

Router01 uptime is 26 weeks, 1 day, 15 hours, 34 minutes
Uptime for this control processor is 26 weeks, 1 day, 15 hours, 47 minutes
System returned to ROM by reload at 15:34:25 UTC Tue Feb 24 2009 (SP by reload)
System restarted at 17:05:40 UTC Tue Jul 28 2009
System image file is "bootdisk:c7600s72033-advipservices-mz.122-33.SRD1.bin"
Last reload type: Normal Reload

cisco CISCO7609 (R7000) processor (revision 1.2) with 983008K/65536K bytes of memory.
Processor board ID FOX103107NH
SR71000 CPU at 600Mhz, Implementation 0x504, Rev 1.2, 512KB L2 Cache
Last reset from s/w reset
5 Virtual Ethernet interfaces
100 Gigabit Ethernet interfaces
12 Ten Gigabit Ethernet interfaces
1917K bytes of non-volatile configuration memory.
8192K bytes of packet buffer memory.

65536K bytes of Flash internal SIMM (Sector size 512K).
Configuration register is 0x2102

Thank you in advance!

--
Have a nice day,
Dmitry

Giuseppe Larosa · ‎01-28-2010

Hello Dmitry,

post

sh ip bgp neigh 80.81.192.A

be aware that if you are trying to setup an eBGP session between not directly connected (using a loopback source) you need

neigh 80.81.192.A ebgp-multihop 2

or other side has not configured the eBGP session or removed their configuration

Hope to help

Giuseppe

kozorezdi · ‎01-28-2010

Hello Giuseppe,

no wrong again

it is direct eBGP peering 80.81.192.C (our ip on DECIX) and 80.81.192.B(remote-AS).

I know that session is exist on remote side, but it down (because of leak of prefixes from my AS).

anyway it should be most time in Active state and just a few seconds in Idle state, at least it was on another models/IOS.

thank you.

#sh ip bgp neighbor 80.81.192.A
BGP neighbor is 80.81.192.A, remote AS B, external link
Description: C
BGP version 4, remote router ID 80.81.192.A
BGP state = OpenSent
Last read 00:00:00, last write 00:00:00, hold time is 180, keepalive interval is 60 seconds
Neighbor sessions:
    0 active, is multisession capable
Message statistics, flags active, state OpenSent:
    InQ depth is 2
    OutQ depth is 0

                         Sent       Rcvd
    Opens:                  1          0
    Notifications:          0          0
    Updates:                0          0
    Keepalives:             0          0
    Route Refresh:          0          0
    Total:                  1          0
Default minimum time between advertisement runs is 30 seconds

For address family: IPv4 Unicast
Session: 80.81.192.A active
BGP table version 73660861, neighbor version 0/0
Output queue size : 0
Index 2, Offset 0, Mask 0x4
2 update-group member
Inbound soft reconfiguration allowed
NEXT_HOP is always this router
Inbound path policy configured
Outbound path policy configured
Route map for incoming advertisements is DE-PEER-DECIX-in
Route map for outgoing advertisements is DE-PEER-DECIX-out
                                 Sent       Rcvd
Prefix activity:               ----       ----
    Prefixes Current:             155          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
Maximum prefixes allowed 3000
Threshold for warning message 75%
Number of NLRIs in the update sent: max 625, min 0

Address tracking is enabled, the RIB does have a route to 80.81.192.A
Connections established 10; dropped 10
Last reset 00:41:55, due to NSF peer closed the session of session 1
Transport(tcp) path-mtu-discovery is enabled
Graceful-Restart is enabled, restart-time 120 seconds, stalepath-time 360 seconds
No active TCP connection

--

Have a nice day,

Dmitry

krushangshah · ‎07-28-2011

Hey Dmitri,

There is possibility that ur physical interface is down. in that case too, bgp state will remain in IDLE.

--

Its FUN !!!

Krushang