[c-nsp] MLPPP and ip load-sharing per-packet

[Rodney Dunn]

MLPPP - more overhead involved
        gives better load "balancing"
        can support fragmentation for voice

CEF pet packet - less overhead
                 gives load *sharing* on a per packet basis
                 *will* cause out of order packets


On Wed, Oct 12, 2005 at 09:31:31AM -0400, Matthew Stainforth wrote:
> 
> I don't mean to hijack the thread but I'm just wondering what the pros and cons of PPP multilink vs CEF per-packet load sharing.
> 
> I ask because I am looking at 2 routers with 4 point to point trans-pacific T1s (100-300 ms latency) between them.  Currently they're using EIGRP to deal with the links separately but I'm thinking multilink or CEF would be a better choice.
> 
> Also, is it the hold-queue that you need to bump up if the re-assembly queue fills up? 
> 
> -----Original Message-----
> From: Oliver Boehmer (oboehmer) [mailto:oboehmer at cisco.com]
> Sent: Wednesday, October 12, 2005 5:25 AM
> To: Shaikh, Nasir; Jon Lewis; Rodney Dunn (rodunn)
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] MLPPP and ip load-sharing per-packet
> 
> 
> Well,
>  if you use MLPPP to create a single Layer3 interface, CEF will not do
> any sort of load-sharing. It will be PPP doing the load distribution,
> and it will make sure to put the fragments/packets back in order. 10-15
> ms difference in latency should be ok, just watch the multilink counters
> in "show ppp multilink" to make sure you're not loosing packets in case
> the re-assembly queue fills up.. why do you want to disable
> fragmentation?
> 
> 	oli
> 
> Shaikh, Nasir <> wrote on Wednesday, October 12, 2005 9:40 AM:
> 
> > Hi,
> > I have a related query, hope someone can help me out here.
> > 
> > I am planning to use MLPPP over 2 ATM pvcs from different providers.
> > Is there any way that I can influence CEF not to use per-packet load
> > balancing? There is about 10-15 ms difference in the latencies of the
> > member links and I 
> > do not want to strain the routers.
> > I will disable fragmentation but will use MQC to ensure WFQ on the
> > ATM pvcs. Purpose of using MLPPP is to make the 2 PVCs appear as one
> > for the routing protocol (EIGRP in this case) and falling back to the
> > shadow pvcs on another router if one or both the member links are
> > down. 
> > 
> > So can I use MLPPP and ensure that CEF does not do per-packet load
> > balancing? 
> > 
> > TIA
> > 
> > Nas
> > 
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net
> > [mailto:cisco-nsp-bounces at puck.nether.net]On Behalf Of Jon Lewis
> > Sent: maandag 10 oktober 2005 14:38
> > To: Rodney Dunn
> > Cc: cisco-nsp at puck.nether.net
> > Subject: Re: [c-nsp] MLPPP and ip load-sharing per-packet
> > 
> > 
> > On Sat, 8 Oct 2005, Rodney Dunn wrote:
> > 
> >> On Sat, Oct 08, 2005 at 10:59:40AM -0400, Jon Lewis wrote:
> >>> I recently converted a group of CEF T1s (ip load-sharing
> >>> per-packet) to MLPPP, but forgot to remove the ip load-sharing
> >>> per-packet from the individual T1s.  Does that command "do
> >>> anything" when the circuits it's applied to are members of a
> >>> multilink group? 
> >> 
> >> Nope. But please remove all commands from the member link T1's.
> > 
> > I suspected not, as it wouldn't make much sense, but we were still
> > having 
> > some issues with VOIP over the the Mu1 interface, so I did go ahead
> > and 
> > remove those.  I suppose it could be that we have brief traffic spikes
> > high enough that I either need more bandwidth or a service-policy
> > giving 
> > VOIP traffic preferential treatment over the Mu1.
> > 
> > ----------------------------------------------------------------------
> >   Jon Lewis                   |  I route
> >   Senior Network Engineer     |  therefore you are
> >   Atlantic Net                |
> > _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
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> > 
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