[c-nsp] BGP maximum-prefix on ASR9000s

[Tim Warnock]

> Have you tested what happens with an XR BGP when a valid peer sends you
> ~2,147,483,647 prefixes please?
> 
> My guess is the BGP runs out of memory and restarts -what happens to the
> FIB on all line-cards I'm not even guessing...
> And then the RRs pushing 2bilions of prefixes to all other PEs in the AS...
> I actually haven't tested so would be interested to know.
> 
> Anyways I'd rather have the offending internet peer/peers reset at around
> 1M or so -while BGP and line-cards can still cope with the load.
> Of course VPN customers have lower thresholds.
> 
> adam
> 

I had some maintenance to perform on an ASR9001 (32bit IOS-XR) - there was a point in time during the maintenance where it only had installed routes from our RRs.

Device#sh bgp all unicast summary wide
Wed Feb 12 13:48:14.246 UTC

Address Family: IPv4 Unicast
----------------------------

BGP router identifier xxxxxxxx, local AS number 38195
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0000000   RD version: 7020912
BGP main routing table version 7020912
BGP NSR Initial initsync version 9 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs

BGP is operating in STANDALONE mode.


Process       RcvTblVer   bRIB/RIB   LabelVer  ImportVer  SendTblVer  StandbyVer
Speaker         7020912    7020912    7020912    7020912     7020912           0

Neighbor                                Spk          AS    MsgRcvd    MsgSent      TblVer       InQ       OutQ    Up/Down  St/PfxRcd
rr-ip                             0       38195     384291        158    7020912          0          0   00:23:06    2297554
rr-ip                             0       38195     384189        157    7020912          0          0   00:22:58    2297548
rr-ip                             0       38195     384858        157    7020912          0          0   00:22:58    2297550


Address Family: IPv6 Unicast
----------------------------

BGP router identifier xxxxxxxx, local AS number 38195
BGP generic scan interval 60 secs
Non-stop routing is enabled
BGP table state: Active
Table ID: 0xe0800000   RD version: 841464
BGP main routing table version 841464
BGP NSR Initial initsync version 6 (Reached)
BGP NSR/ISSU Sync-Group versions 0/0
BGP scan interval 60 secs

BGP is operating in STANDALONE mode.


Process       RcvTblVer   bRIB/RIB   LabelVer  ImportVer  SendTblVer  StandbyVer
Speaker          841464     841463     841464     841463      841463           0

Neighbor                                Spk          AS    MsgRcvd    MsgSent      TblVer       InQ       OutQ    Up/Down  St/PfxRcd
rr-ip                             0       38195     104261        145     841463          0          0   00:23:06     249910
rr-ip                             0       38195     104244        143     841463          0          0   00:22:48     249910
rr-ip                             0       38195     104322        145     841463          0          0   00:23:06     249910


Happy to report that it didn't explode.

Thanks
Tim.