[188193] in North American Network Operators' Group
Figuring out traceroute
daemon@ATHENA.MIT.EDU (Reza Motamedi)
Thu Mar 10 19:25:15 2016
X-Original-To: nanog@nanog.org
From: Reza Motamedi <motamedi@cs.uoregon.edu>
Date: Thu, 10 Mar 2016 16:24:41 -0800
To: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
Hi guys,
This might seem a bit of a trivial question, but I guess there is no harm
in asking. I am looking at a collection of traceroutes all go through the
following consecutive hops (* >> 213.248.98.238), as shown here (I kept the
DNSname just for completeness):
+ From >> To
+ (213.155.130.125:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.130.127:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.131.75:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.131.83:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.131.85:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.134.251:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.134.253:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.134.77:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.137.57:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (213.155.137.59:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.114.111:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.168:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.170:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.174:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.176:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.178:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.180:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.182:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.184:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.186:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.188:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.116.190:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.140.253:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
+ (62.115.140.255:las-b3-link.telia.net) >> (213.248.98.238:b
harti-ic-140621-las-b3.c.telia.net)
Given the way traceroute works (most of the times), which reports back the
ingress port of the router it hits, do you think it fair to assume that all
the hops that I see on the `From` hop are all different ports of one
router? I think the other explanation is that there is switch (or something
that does not have IP footprint) between `From` side and `To` side. How
probable do you think this second explanation is?
Best Regards
Reza Motamedi (R.M)
