Question on traceroute

kawin · ‎03-25-2002

Hi all,

Have a question when I traceroute from my border router. When I trace to www.yahoo.com, it looks like a normal traceroute.

When I trace to www.excite.com, there are three entries for each hop, and the first and third are the same.

I'm more concerned with why there's two identical-looking routes on each hop....anyone can help?

Type escape sequence to abort.

Tracing the route to www.yahoo.akadns.net (64.58.76.179)

1 209.73.229.249 [AS 4513] 4 msec 0 msec 4 msec

2 ge4-0-core1.nyc1.globix.net (209.10.0.193) [AS 4513] 4 msec 4 msec 4 msec

3 ge4-0-peer3.nyc1.globix.net (209.10.12.114) [AS 4513] 0 msec 4 msec 4 msec

4 exodus-globix.nyc1.globix.net (209.10.13.214) [AS 4513] 4 msec 4 msec 24 msec

5 216.74.171.2 [AS 3967] 4 msec 4 msec 4 msec

6 bbr01-p1-0.nycm01.exodus.net (206.79.9.117) [AS 3967] 4 msec 4 msec 4 msec

7 bbr01-p0-0.stng01.exodus.net (206.79.9.102) [AS 3967] 8 msec 12 msec 8 msec

8 dcr04-g7-0.stng01.exodus.net (216.33.99.100) [AS 3967] 8 msec 12 msec 12 msec

9 csr22-ve241.stng01.exodus.net (216.33.98.19) [AS 3967] 8 msec 8 msec 12 msec

10 216.35.210.126 [AS 3967] 12 msec 8 msec 12 msec

11 www.yahoo.akadns.net (64.58.76.179) [AS 3967] 8 msec 8 msec 12 msec

SoundScan#traceroute www.excite.com

Translating "www.excite.com"...domain server (209.10.66.23) [OK]

Type escape sequence to abort.

Tracing the route to (208.45.133.23)

1 839.ATM5-0.GW11.NYC1.ALTER.NET (65.217.194.141) [AS 701] 4 msec

676.ATM1-0.GW4.NYC4.ALTER.NET (65.217.194.145) [AS 701] 0 msec

839.ATM5-0.GW11.NYC1.ALTER.NET (65.217.194.141) [AS 701] 4 msec

2 146.at-5-1-0.XR3.NYC4.ALTER.NET (152.63.25.98) [AS 701] 4 msec

585.at-6-0-0.XL2.NYC1.ALTER.NET (152.63.22.150) [AS 701] 4 msec

146.at-5-1-0.XR3.NYC4.ALTER.NET (152.63.25.98) [AS 701] 4 msec

3 308.at-1-1-0.XR2.NYC8.ALTER.NET (152.63.28.21) [AS 701] 12 msec

209.at-1-0-0.XR1.NYC8.ALTER.NET (152.63.28.229) [AS 701] 4 msec

308.at-1-1-0.XR2.NYC8.ALTER.NET (152.63.28.21) [AS 701] 16 msec

4 183.ATM7-0.BR1.NYC8.ALTER.NET (152.63.23.169) [AS 701] 4 msec

182.ATM5-0.BR1.NYC8.ALTER.NET (152.63.23.77) [AS 701] 16 msec

183.ATM7-0.BR1.NYC8.ALTER.NET (152.63.23.169) [AS 701] 4 msec

5 jfk-brdr-02.inet.qwest.net (205.171.4.9) [AS 209] 52 msec 52 msec 48 msec

6 jfk-core-03.inet.qwest.net (205.171.230.26) [AS 209] 52 msec 52 msec 52 msec

7 ewr-core-03.inet.qwest.net (205.171.5.89) [AS 209] 48 msec 52 msec 52 msec

8 ewr-cntr-02.inet.qwest.net (205.171.17.150) [AS 209] 52 msec 52 msec 52 msec

9 msfc-70.ewr.qwest.net (63.146.100.11) [AS 209] 52 msec 52 msec 48 msec

10 208.47.215.67 [AS 209] 404 msec 436 msec 408 msec

11 10.10.8.3 48 msec

10.10.8.2 52 msec

10.10.8.3 48 msec

rais · ‎03-25-2002

Looks like you had dual equal-cost routes to exicte for sometime.

Gilles Dufour · ‎03-26-2002

it's normal. You have loadbalancing over multiple path.

mberrocal · ‎03-26-2002

what hapens is that traceroute sends 3 datagrams for each hop. So, when you see different host in the same row number, it means each of the 3 udp datagrams went to a diferent router (or in your case 2 went to one router). This is common in load-balancing: the first packet goes out one interface but the next goes out to another, then the third packet goes thru the first interface, and so on.

you may find the following link helpfull:

http://www.cisco.com/warp/public/63/ping_traceroute.html#traceroute