[166874] in North American Network Operators' Group
Re: Question on routing of Tata AS6453 with their other network AS4755
daemon@ATHENA.MIT.EDU (Erik Bais)
Sat Nov 16 15:25:26 2013
In-Reply-To: <CAJ0+aXZ1E9zvVP7PgLrMOELdRa3fYcPM7pbgZtJNofcEZMP3wA@mail.gmail.com>
From: Erik Bais <ebais@a2b-internet.com>
Date: Sat, 16 Nov 2013 21:24:55 +0100
To: Anurag Bhatia <me@anuragbhatia.com>
Cc: NANOG Mailing List <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
We have a ticket open with Tata currently on a similar issue.=20
Traffic from our AS (51088) via Tata to DTAG goes from Amsterdam, NL, to Tat=
a Frankfurth, Germany, to Tata Paris, France, to DTAG In Paris, back to Germ=
any ?? With packetloss...=20
Our Tinet (GT-T) routes go from Amsterdam to DTAG ( Amsterdam) to Germany ..=
=20
No reply on the ticket yet where the packetloss comes from or why they are r=
outing via Paris which adds about 30 ms ...
Check out our Smokeping page for it ..=20
http://smokeping.a2b-internet.com/smokeping/smokeping.cgi?target=3DLatencyCh=
eckList.Tata_Paris
We are currently pref'ing the traffic to DTAG via Tinet/ GT-T.=20
Erik Bais
A2B Internet=20
Verstuurd vanaf mijn iPad
Op 16 nov. 2013 om 20:49 heeft Anurag Bhatia <me@anuragbhatia.com> het volge=
nde geschreven:
> Hello everyone
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> I was looking around and noticed a pretty bad route from DTAG to Tata
> AS6453 (basically destination was Tata Comm's Indian network on AS4755). I=
> am not able to understand cause for inefficient routing but I am sure I am=
> failing to understand something which is crazy in their IGP. The result is=
> that route from Europe to India is via Europe > US > Singapore > India
> rather then direct India.
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> There seem to be quite a few prefixes with these problem, but for this mai=
l
> question, I am picking two prefixes - one which seems to be having good
> routing.
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> 202.54.82.0/24 has pretty bad routing while 93.183.28.0/24. I see both
> prefixes have valid route objects and are originated by VSNL AS4755 to Tat=
a
> AS6453 in India. Now if we compare trace from Tata's own core router say i=
n
> Paris from their looking glass, I get:
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> Router: gin-pye-core1
> Site: FR, Paris, PYE
> Command: traceroute ip 202.54.82.1
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> Tracing the route to RAS55.1.ppppun.vsnl.net.in (202.54.82.1)
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> 1 if-1-0-0-2.tcore1.PYE-Paris.as6453.net (80.231.154.45) [MPLS: Label
> 525297 Exp 0] 300 msec
> if-0-0-0-0.tcore1.PYE-Paris.as6453.net (80.231.154.37) [MPLS: Label
> 525297 Exp 0] 260 msec
> if-1-0-0-2.tcore1.PYE-Paris.as6453.net (80.231.154.45) [MPLS: Label
> 525297 Exp 0] 260 msec
> 2 if-5-2.tcore1.L78-London.as6453.net (80.231.130.1) [MPLS: Label 523604
> Exp 0] 264 msec
> if-3-6.tcore1.L78-London.as6453.net (80.231.130.85) [MPLS: Label 523604=
> Exp 0] 256 msec
> if-5-2.tcore1.L78-London.as6453.net (80.231.130.1) [MPLS: Label 523604
> Exp 0] 264 msec
> 3 if-2-2.tcore2.L78-London.as6453.net (80.231.131.1) [MPLS: Label 728466
> Exp 0] 264 msec
> * if-1-2.tcore2.L78-London.as6453.net
> <http://if-1-2.tcore2.L78-London.as6453.net> (80.231.130.122) [MPLS: Label=
> 728466 Exp 0] 264 msec 268 msec*
> * 4 if-20-2.tcore2.NYY-NewYork.as6453.net
> <http://if-20-2.tcore2.NYY-NewYork.as6453.net> (216.6.99.13) [MPLS: Label
> 354225 Exp 0] 276 msec 260 msec 260 msec*
> 5 *
> if-12-6.tcore1.CT8-Chicago.as6453.net (216.6.99.46) [MPLS: Label 365409=
> Exp 0] 304 msec
> if-11-2.tcore1.NYY-NewYork.as6453.net (216.6.99.2) [MPLS: Label 782881
> Exp 0] 256 msec
> 6 if-22-2.tcore2.CT8-Chicago.as6453.net (64.86.79.1) [MPLS: Label 361921
> Exp 0] 264 msec 264 msec
> if-1-2.tcore1.PDI-PaloAlto.as6453.net (66.198.127.5) [MPLS: Label
> 670352 Exp 0] 256 msec
> 7 if-11-3.tcore2.PDI-PaloAlto.as6453.net (66.198.144.57) [MPLS: Label
> 321233 Exp 0] 256 msec
> if-2-2.tcore2.PDI-PaloAlto.as6453.net (66.198.127.2) [MPLS: Label
> 321233 Exp 0] 260 msec *
> 8 if-9-2.tcore1.TV2-Tokyo.as6453.net (180.87.180.18) 280 msec 260 msec
> 260 msec
> 9 if-2-2.tcore2.TV2-Tokyo.as6453.net (180.87.180.2) [MPLS: Label 581761
> Exp 0] 252 msec 252 msec 252 msec
> 10 if-6-2.tcore1.SVW-Singapore.as6453.net (180.87.12.109) [MPLS: Label
> 710034 Exp 0] 248 msec 244 msec 248 msec
> 11 if-5-2.tcore1.CXR-Chennai.as6453.net (180.87.12.54) 244 msec 272 msec
> 252 msec
> 12 180.87.36.10 272 msec 256 msec 272 msec
> 13 172.31.19.94 272 msec 252 msec 256 msec
> 14 * *
> 172.25.83.142 288 msec
> 15 172.25.83.134 !H * *
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> while for other prefix, route is:
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> Router: gin-pye-core1
> Site: FR, Paris, PYE
> Command: traceroute ip 93.183.28.1
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> Tracing the route to 93.183.28.1
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> 1 if-1-0-0-2.tcore1.PYE-Paris.as6453.net (80.231.154.45) [MPLS: Label
> 519713 Exp 0] 12 msec
> if-0-0-0-0.tcore1.PYE-Paris.as6453.net (80.231.154.37) [MPLS: Label
> 519713 Exp 0] 12 msec
> if-1-0-0-2.tcore1.PYE-Paris.as6453.net (80.231.154.45) [MPLS: Label
> 519713 Exp 0] 12 msec
> 2 if-8-1600.tcore1.WYN-Marseille.as6453.net (80.231.217.5) [MPLS: Label
> 302880 Exp 0] 12 msec
> if-14-2.tcore1.WYN-Marseille.as6453.net (80.231.154.170) [MPLS: Label
> 302880 Exp 0] 36 msec
> if-8-1600.tcore1.WYN-Marseille.as6453.net (80.231.217.5) [MPLS: Label
> 302880 Exp 0] 12 msec
> *3 if-2-2.tcore2.WYN-Marseille.as6453.net
> <http://if-2-2.tcore2.WYN-Marseille.as6453.net> (80.231.217.2) 12 msec 12
> msec 12 msec*
> 4 80.231.200.26 140 msec 116 msec 116 msec
> 5 172.31.16.193 148 msec 140 msec 144 msec
> * 6 115.114.71.133.static-chennai.vsnl.net.in
> <http://115.114.71.133.static-chennai.vsnl.net.in> (115.114.71.133) [AS
> 4755] 140 msec 148 msec 140 msec*
> 7 172.29.209.82 [MPLS: Labels 301664/7167 Exp 1] 148 msec 144 msec 148
> msec
> 8 172.31.35.138 [MPLS: Labels 4831/7167 Exp 1] 152 msec 152 msec 148 msec=
> 9 121.242.126.205.static-chennai.vsnl.net.in (121.242.126.205) [AS 4755]
> [MPLS: Label 7167 Exp 1] 148 msec * 140 msec
> 10 121.242.126.206.static-chennai.vsnl.net.in (121.242.126.206) [AS 4755]
> 140 msec 148 msec 140 msec
> 11 * * *
> 12 * * *
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> Now if I focus on best route entry in router for both prefixes, I see
> following:
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> Bad Prefix:
> 4755
> tv2-tcore1. (metric 16148) from *hk2-core3.* (hk2-core3.)
> Origin IGP, valid, internal, best
> Community:
> Originator: 66.110.10.113
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> Good Prefix:
> 4755
> wyn-tcore2. (metric 10050) *from wyn-tcore2.* (66.110.10.109)
> Origin IGP, valid, internal, best
> Community:
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> Now as I understand Paris router is getting bad prefix from TV2 which is
> their Tokyo router while for other prefix with good routing, route is via
> their other router on cable landing station in France.
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> Can someone explain me what exactly is happening here? Are they missing
> some iBGP sessions? It's not perfect mesh & missing route reflectors?
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> Probably both prefixes are originated inside India by different routers bu=
t
> as I understand all prefixes get transit from AS6453 and so is it like
> AS6453 missing some routes (which seem to be direct) to technically
> downstream AS4755?
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> Curious to hear your thoughts.
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> Note: I am not worried about issue - it's not really impacting me. Just
> trying to learn what is wrong in the backbone design here.
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> Thanks.
> --=20
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> Anurag Bhatia
> anuragbhatia.com
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> Linkedin <http://in.linkedin.com/in/anuragbhatia21> |
> Twitter<https://twitter.com/anurag_bhatia>
> Skype: anuragbhatia.com
