Re: [Idr] draft-walton-bgp-hostname-capability-00

[Robert Raszuk <[e-mail]>]

Hi Dinesh,

Q1 - how do you ping physical interface not a loopback

Q2 - how about lookup on bgp rtr id instead LL address to get the name ?

Cheers,
R.

On Saturday, May 16, 2015, Dinesh Dutt <[e-mail]> wrote:

> Hi Robert,
>
> On Fri, May 15, 2015 at 11:01 PM, Robert Raszuk <[e-mail]
> <javascript:_e(%7B%7D,'cvml','[e-mail]');>> wrote:
>
>> Hi Daniel & Dinesh,
>>
>> I very much like the intention, but have a concern how it would simplify
>> troubleshooting in practice ...
>>
>> Imagine we exchange the names in new capability when session comes up so
>> we list it in summary output instead of link local address. But when you
>> try to trace or ping that name (from pc or router) your local or global DNS
>> will return not the LL address but most likely loopback so the results will
>> be rather of questionable value.
>>
>
> I'm confused. Why would we send a hostname in this capability that is
> different from the one assigned to loopback ? Within the DC at least,
> people don't advertise link addresses at all, only the loopback.  So, the
> hostname exchanged in the capability would be the same as the one returned
> by traceroute/ping.
>
> Dinesh
>
>
>> Would you not see this as a problem ? I hope you did not intended to just
>> cover the cosmetic nature of few show commands which I must agree with
>> others is rather a legacy way to operate the network these days anyway ;)).
>>
>
>
>
>>
>> Cheers,
>> R.
>>
>>
>> On Saturday, May 16, 2015, Daniel Walton <[e-mail]
>> <javascript:_e(%7B%7D,'cvml','[e-mail]');>> wrote:
>>
>>> Many of our customers use a Clos architecture and bgp peer to the IPv6
>>> LL address of every directly connected router.  To avoid configuring
>>> neighbor statements with LL addresses we support a "neighbor swpX
>>> interface" command ("swpX" is the default notation for an interface name in
>>> cumulus linux).  We then peer to the LL address on the other end of the
>>> swpX link (we only support this for point-to-point links).
>>>
>>> When you run commands like "show ip bgp summary" you see a list of
>>> interface names instead of IP addresses. Typically if you are loopback
>>> peering you either become familiar with "10.0.0.1 is Chicago" because you
>>> see 10.0.0.1 in the 'show ip bgp summ' output of several different routers
>>> or you could use DNS to do a lookup on 10.0.0.1 and put the hostname in the
>>> output.  When every box is peering to LL addresses though ("swpX" for short
>>> for us) you can't easily tell who that peer is and you can't use DNS
>>> because they LL addresses
>>>
>>> *Before*
>>>
>>> leaf-11# show ip bgp summ
>>> BGP router identifier 6.0.0.5, local AS number 65101
>>> BGP table version 25
>>> RIB entries 33, using 3960 bytes of memory
>>> Peers 6, using 100 KiB of memory
>>> Peer groups 1, using 56 bytes of memory
>>>
>>> Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down
>>>  State/PfxRcd
>>> swp1            4 65000     196     198        0    0    0 00:02:51
>>>    9
>>> swp2            4 65000     195     200        0    0    0 00:02:51
>>>    9
>>> swp3            4 65000     197     200        0    0    0 00:02:51
>>>    9
>>> swp4            4 65000     198     200        0    0    0 00:02:51
>>>    9
>>> swp5            4 65201     207     200        0    0    0 00:02:51
>>>    2
>>> swp6            4 65202     210     201        0    0    0 00:02:52
>>>    2
>>>
>>> Total number of neighbors 6
>>> leaf-11#
>>>
>>> spine-3# show ip bgp summ
>>> BGP router identifier 6.0.0.15, local AS number 65000
>>> BGP table version 19
>>> RIB entries 33, using 3960 bytes of memory
>>> Peers 8, using 134 KiB of memory
>>> Peer groups 1, using 56 bytes of memory
>>>
>>> Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down
>>>  State/PfxRcd
>>> swp5            4 65101     675     675        0    0    0 00:10:49
>>>    5
>>> swp6            4 65101     678     676        0    0    0 00:10:50
>>>    5
>>> swp7            4 65101     667     668        0    0    0 00:10:48
>>>    5
>>> swp8            4 65101     676     676        0    0    0 00:10:49
>>>    5
>>> swp9            4 65102     701     692        0    0    0 00:11:04
>>>    5
>>> swp10           4 65102     701     692        0    0    0 00:11:04
>>>    5
>>> swp11           4 65102     701     691        0    0    0 00:11:04
>>>    5
>>> swp12           4 65102     701     692        0    0    0 00:11:04
>>>    5
>>>
>>> Total number of neighbors 8
>>> spine-3#
>>> spine-3#
>>>
>>>
>>> *After*
>>>
>>> leaf-11# show ip bgp summ
>>> BGP router identifier 6.0.0.5, local AS number 65101
>>> BGP table version 25
>>> RIB entries 33, using 3960 bytes of memory
>>> Peers 6, using 100 KiB of memory
>>> Peer groups 1, using 56 bytes of memory
>>>
>>> Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down
>>>  State/PfxRcd
>>> spine-1(swp1)   4 65000     211     213        0    0    0 00:03:07
>>>    9
>>> spine-2(swp2)   4 65000     210     215        0    0    0 00:03:07
>>>    9
>>> spine-3(swp3)   4 65000     212     215        0    0    0 00:03:07
>>>    9
>>> spine-4(swp4)   4 65000     213     215        0    0    0 00:03:07
>>>    9
>>> tor-11(swp5)    4 65201     222     215        0    0    0 00:03:07
>>>    2
>>> tor-12(swp6)    4 65202     225     216        0    0    0 00:03:08
>>>    2
>>>
>>> Total number of neighbors 6
>>> leaf-11#
>>>
>>> spine-3# show ip bgp summ
>>> BGP router identifier 6.0.0.15, local AS number 65000
>>> BGP table version 19
>>> RIB entries 33, using 3960 bytes of memory
>>> Peers 8, using 134 KiB of memory
>>> Peer groups 1, using 56 bytes of memory
>>>
>>> Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down
>>>  State/PfxRcd
>>> leaf-11(swp5)   4 65101    1119    1119        0    0    0 00:18:13
>>>    5
>>> leaf-12(swp6)   4 65101    1122    1120        0    0    0 00:18:14
>>>    5
>>> leaf-13(swp7)   4 65101    1110    1111        0    0    0 00:18:12
>>>    5
>>> leaf-14(swp8)   4 65101    1119    1119        0    0    0 00:18:13
>>>    5
>>> leaf-21(swp9)   4 65102    1144    1135        0    0    0 00:18:28
>>>    5
>>> leaf-22(swp10)  4 65102    1144    1135        0    0    0 00:18:28
>>>    5
>>> leaf-23(swp11)  4 65102    1144    1134        0    0    0 00:18:28
>>>    5
>>> leaf-24(swp12)  4 65102    1144    1135        0    0    0 00:18:28
>>>    5
>>>
>>> Total number of neighbors 8
>>> spine-3#
>>>
>>> It makes troubleshooting much easier.
>>>
>>> Daniel
>>>
>>>
>>> On Fri, May 15, 2015 at 9:58 PM, <[e-mail]> wrote:
>>>
>>>> Agree.. adding code for no real operational benefit
>>>>
>>>> Sent from my BlackBerry 10 smartphone on the Rogers network.
>>>>   Original Message
>>>> From: Randy Bush
>>>> Sent: Friday, May 15, 2015 10:52 PM
>>>> To: Daniel Walton
>>>> Cc: idr wg; Dinesh Dutt
>>>> Subject: Re: [Idr] draft-walton-bgp-hostname-capability-00
>>>>
>>>> one more unneeded place for things to go wrong
>>>>
>>>> randy
>>>>
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>>>>
>>>
>>>
>