I really like Daniel Walton‘s draft-walton-bgp-hostname-capability-00. Cumulus Networks implemented this as part of Quagga/FRR and it has become to default on Cumulus Linux 3.0 and later. BGP is one of those protocols that is really powerful but in the past is really a pain in the ass to troubleshoot if you don’t know how things are cabled. Without a network map or diagram it will take awhile to reverse engineer and troubleshoot a customer’s network.
This capability allows the configured BGP neighbor hostname to be shared via BGP (not lldp or cdp) so it can give you the output with the BGP commands themselves without having to correlate a neighbor to IP address, and IP address to physical switchport. What does that look like?
cumulus@leaf01:mgmt-vrf:~$ net show bgp sum show bgp ipv4 unicast summary ============================= BGP router identifier 10.0.0.11, local AS number 65011 vrf-id 0 BGP table version 107 RIB entries 25, using 3400 bytes of memory Peers 2, using 42 KiB of memory Peer groups 1, using 72 bytes of memory Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd spine01(swp51) 4 65020 286176 286211 0 0 0 01w2d22h 11 spine02(swp52) 4 65020 224758 224766 0 0 0 4d18h12m 11
Wow… that is beautiful. Now I know my two uplinks (switchport 51 and switchport 52) are hooked up to spine01 and spine02. the output without this default (“no bgp default show-hostname”) looks like this:
cumulus@leaf01:mgmt-vrf:~$ net show bgp sum show bgp ipv4 unicast summary ============================= BGP router identifier 10.0.0.11, local AS number 65011 vrf-id 0 BGP table version 107 RIB entries 25, using 3400 bytes of memory Peers 2, using 42 KiB of memory Peer groups 1, using 72 bytes of memory Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd swp51 4 65020 286341 286376 0 0 0 01w2d22h 11 swp52 4 65020 224923 224931 0 0 0 4d18h21m 11
I use this for every customer network I work on (which is easy now that it is the default). I hope more and more vendors implement this capability because it is very slick.
Let me know what you think in the comments, I will talking about new features in BGP that we have been using for awhile but might not be that common outside of Cumulus Networks.