[j-nsp] MTU Compression

[Ben Dale]

For future reference, TCP-MSS adjustment can be achieved on flow-blased boxes (J/SRX) using:

set security flow tcp-mss all-tcp mss 1380

and on M/T (and probably MX) using:

set services service-set <SERVICE-SET-NAME > tcp-mss 1380

This won't help you with MPLS-encapsulated traffic though - to shrink that you'll need to drop your MPLS into a GRE tunnel, then fragment the GRE packets down below your interface MTU and re-assemble them on the other side.  My only experience with this is on the SRX and it's a convoluted process, but it seems to work pretty well.


On 08/07/2010, at 6:55 AM, Humair Ali wrote:

> Hi Guys
> 
> Many thanks for your feedback,
> 
> The issue is that the circuit is limited by their kit to 1518 and can't
> provide more ,
> 
> There is MPLS headers on top on top of the 1518,
> 
> We have manage to get a resolution with the provider to be put on different
> circuit through a hardware that does supports more than 1518.
> 
> So hopefully we will be able to provide the service without having to tweak
> the MSS.
> 
> Many thanks for your help guys
> 
> Much appreciated
> 
> On 7 July 2010 21:12, Robert J. Huey <rhuey at anzus.com> wrote:
> 
>> 
>> The motivation for this requirement is not all that clear and I suspect may
>> have some bearing on a solution.    Is the backbone requirement because your
>> forwarding on MPLS headers?  If so, I do not think that any of the MSS
>> tweaks are going to help you.   Unfortunately, your third party circuit
>> leaves you very little wiggle room, you might just be out of luck on that
>> path.   Conversely, if the requirement is coming from the application side,
>> you might consider a WAN Optimization Controller....     It's not a straight
>> forward payload compression thing, but I think that they can operate in any
>> point-to-point Ethernet environment and effectively proxy the TCP sessions
>> locally.  that might get you bye.  good luck
>> 
>> rgds,
>>   --r
>> 
>> 
>> 
>> On Jul 7, 2010, at 1:59 AM, Humair Ali wrote:
>> 
>>> Hi All
>>> 
>>> MX480
>>> Junos 9.6 R3
>>> 
>>> We are experiencing some MTU issue on one of our circuit.
>>> 
>>> We have been provided a circuit by a 3rd party provider that only
>> supports
>>> MTU size 1518,
>>> 
>>> Unfortunately it seems they cannot provide Jumbo Frames,
>>> 
>>> However for our backbone we required to have Jumbo Frames supported.
>>> 
>>> My question is , is there any such option as MTU compression available ?
>>> 
>>> something that would allow a packet of 9192 coming into our MX480 , then
>> be
>>> comrpessed to 1518 accross the Circuit provider link, then De-compress on
>>> our MX480 on the other end ?
>>> 
>>> I have been looking on docs but couldnt anything as such
>>> 
>>> your help much appreciate, if someone came accross similar and found a
>>> workaround , please share
>>> 
>>> Thanks
>>> _______________________________________________
>>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>>> https://puck.nether.net/mailman/listinfo/juniper-nsp
>> 
>> 
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