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Re: T1 bonding
From: Elijah Savage <esavage () digitalrage org>
Date: Tue, 24 Jan 2006 20:26:26 -0500

Hash: SHA1

Scott Morris wrote:
I'm re-reading it, and slowly, but I don't see mention of having two
different vendors.  Perhaps I need to put the beer a bit further away, but
he talks about generic vendor 'x' and notes that it starts with letter 'A'
as further definition, not as two separate vendors.



-----Original Message-----
From: Elijah Savage [mailto:esavage () digitalrage org] 
Sent: Tuesday, January 24, 2006 8:20 PM
To: swm () emanon com
Cc: 'Matt Bazan'; nanog () merit edu
Subject: Re: T1 bonding

Scott Morris wrote:
If you're treating them as two separate links (e.g. two POPs, etc.) 
then that's correct, it'll be done by the routers choice of load-balancing
If you are going to the same POP (or box potentially) you can do MLPPP 
and have a more effective L2 load balancing.

Otherwise, it's possible to get an iMux DSU (Digital Link is a vendor 
as I recall, but there may be others) that allow that magical bonding 
to occur prior to the router seeing the link.  At that point, the 
router just sees a bigger line coming in (some do 6xT-1 and have a 
10meg ethernet output to your router).

If you're seeing the balancing the way that you are, most likely that 
vendor (I have no specific knowledge about the A-vendor) is doing 
usage-based aggregation which isn't exactly a balancing act.  The ones 
at some of my sites are MLPPP which is a vendor-agnostic approach for the
most part.

-----Original Message-----
From: owner-nanog () merit edu [mailto:owner-nanog () merit edu] On Behalf 
Of Elijah Savage
Sent: Tuesday, January 24, 2006 7:28 PM
To: Matt Bazan
Cc: nanog () merit edu
Subject: Re: T1 bonding

Matt Bazan wrote:
Can someone shed some technical light on the details of how two T1's 
are bonded (typically).  We've got two sets of T's at two different 
location with vendor 'X' (name starts w/ an 'A') and it appears that 
we're really only getting about 1 full T's worth of bandwidth and 
maybe 20% of the second.

Seems like they're bonded perhaps using destination IP?  It's a 
vendor managed solution and I need to get some answers faster than 
they're coming in.  Thanks.


More than likely they are not bonded t1's they are just load balanced 
by the router which by default on Cisco is per session. Meaning pc1 to 
t1#1, pc2to t1#2, pc3 to t1#1. If they are truly bonded with some sort 
of MUX for a 3 meg port then you would not see the results you are seeing.

The Information Technology News Center
Remember he said both t1's are coming from different vendors, which would
only leave the Mux route which is why I said what I said :)
The Information Technology News Center
Uh Scott I think it is I whom by the way is getting up right now and
going to put the rest of the beer back in the fridge. OOOOPS
- --
The Information Technology News Center
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