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RE: T1 bonding

  • From: Scott Morris
  • Date: Tue Jan 24 20:24:51 2006

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 [] 
Sent: Tuesday, January 24, 2006 8:20 PM
Cc: 'Matt Bazan';
Subject: Re: T1 bonding

Hash: SHA1

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.
> Scott
> -----Original Message-----
> From: [] On Behalf 
> Of Elijah Savage
> Sent: Tuesday, January 24, 2006 7:28 PM
> To: Matt Bazan
> Cc:
> 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.
>>>   Matt
> 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
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