From: Church, Chuck (cchurch@wamnetgov.com)
Date: Sat Jan 31 2004 - 19:06:38 GMT-3
It looks like it's working. MS's tracert sends 3 packets at each TTL, to give you an average. In the case of trace 1, you're getting responses from 2 alternating sources. I find it odd though that the result shows load balancing along 2 hops. I assume you've only got 1 interface each between the hosts and the routers. But your first hop is getting TTL expired messages from 2 separate interfaces, where it would normally be sourced by that LAN interface you're attached to. Maybe this is just a by-product of the method you're using to get per-packet load balancing (since they're all part of the same flow, but being balanced anyway). Normally, you'd get a response from the LAN interface on hop 1, and then the second hop would be from R2's 2 serial interfaces, assuming tracing from A to B. But you're getting responses from R1's two serial interfaces instead. Seems a little odd, but I believe it's working. Examining the packet counts on the serial interfaces would verify!
it as well.
Chuck Church
CCIE #8776, MCNE, MCSE
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch@wamnetgov.com
PGP key: http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40wamnetgov.com
> -----Original Message-----
> From: alsontra@hotmail.com [mailto:alsontra@hotmail.com]
> Sent: Thursday, January 29, 2004 9:41 PM
> To: ccielab@groupstudy.com
> Subject: Traceroute and load balencing
>
>
> Group,
>
> I think I know the answer to this one, but I would like to be
> sure. The
> example topology is as follows:
>
> ________
> Host A ----R1_______ R2------ Host B
>
>
> R1 and R2 are doing load balancing OSPF, EIGRP, whatever its
> not important.
>
>
> Host A pings Host B and the trace that comes back should not
> be exactly linear
> correct? Load balancing would cause some packets to take
> route 1 vs. route 2.
> (round robin)
>
>
> I have a similar situation in my home lab and want to make
> sure what I'm
> seeing is actual the result of load balancing.
>
>
> The traces look something like this when I have load
> balancing enabled.
>
> Tracing the route to 111.1.1.1
>
> 1 160.1.1.6 4 msec
> 150.1.1.2 0 msec
> 160.1.1.6 0 msec
> 2 141.1.1.5 32 msec
> 141.1.1.9 36 msec
> 141.1.1.5 36 msec
> 3 171.1.1.3 36 msec 36 msec 32 msec
> 4 180.1.1.8 36 msec
>
>
> And when only one link is available the trace looks like this:
>
> Tracing the route to 111.1.1.1
>
> 1 160.1.1.6 0 msec 4 msec 4 msec
> 2 141.1.1.9 28 msec 32 msec 36 msec
> 3 171.1.1.3 32 msec 36 msec 32 msec
> 4 180.1.1.8 36 msec * 32 msec
>
>
>
> All ping attempts are successful and no data is ever lost.
> I'd just like to
> verify that traceroute is actually displaying load balancing.
>
>
> Alsontra
>
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