[c-nsp] Cisco MultiLink PPP

Thu Mar 24 10:39:02 EST 2005

On Thu, Mar 24, 2005 at 07:25:46AM -0800, Richard J. Sears wrote:
> Hi Rodney,
> 
> Would 7513's running 12.2(27) have problems with MLPPP...? We had to
> convert all of our MLPPP customers to ip load sharing per packet because
> we would lose the mlppp links and the only way to get them back was to
> reboot the router. I would like to use MLPPP, but I (like many) have had
> horrible headaches with it.
> 
> We are running around 300 T1s per 7513 with RSP4s.

The customer I worked with closely had 800+ interfaces
running at various rates with Gig uplinks to the core.

Leased line aggregation.  Average uplink bw usage was
around 100 Mbps spread over two GEIP+ boards.

The downstreams are all MCT3 PA's channelized out.

No heavy features (QOS, ACL's etc..)

The maximum number of interfaces you can have is like
832 I think (that's the QA ASIC limiation).
That isn't software IDB's (tunnels, subints, etc..).

While I'd like to say all those bugs were back ported
to 12.2 I don't think that was done because at the time
we didn't have any customers doing it.

Your best bet would be 12.3 or 12.0S.

There will be a 12.2S version coming out for the 75xx
at some point that has more MPLS/MLPPP feature interaction
support.

Rodney

> 
> Thanks
> 
> On Thu, 24 Mar 2005 09:24:39 -0500
> Rodney Dunn <rodunn at cisco.com> wrote:
> 
> > I've worked through a lot of those bugs on the 75xx
> > and we did have some bad ones.
> > 
> > All the ones I know of have been fixed in later 12.0S 
> > code and latest 12.2 and 12.3 mainline
> > code.
> > 
> > You were most likely hitting:
> > 
> > CSCed29590
> > Multilink PPP link flap causes output frozen for member link
> > 
> > which was the worst one.
> > 
> > I've seen lots of large customers running dMLP on
> > a 75xx running stable for over a year.
> > 
> > My recommendation would be 12.0(27)S4 or 12.3(13).
> > 
> > What I find is most people don't have the box setup
> > properly to be running in fully distributed mode so the
> > bundles are distributed and/or their VIPs don't have the
> > CPU power to handle the bundles.
> > 
> > 
> > Rodney
> > 
> > 
> > CSCeg28064
> > Internally found moderate defect: Assigned (R)
> > cbus complex results in incorrect multilink state
> > 
> > CSCeb31029
> > Internally found moderate defect: Resolved (R)
> > Output rates incorrect on dMLP/dMFR/dLFI interfaces under congestion
> > 
> > CSCee69493
> > Externally found moderate defect: Resolved (R)
> > dMLP fails if control is given to IOS MLPPP
> > 
> > CSCin36465 Watchdog crashed because of MLPPP
> > 
> > CSCin47712 txacc loss after OIR
> > 
> > CSCec00268 Input drops and * throttles on PPP multilink interface
> > 
> > CSCea59948 Output stuck on a T3 Port Adaptor
> > 
> > CSCec87815
> > Multilink buffer header leak on a VIP with an ATM PA installed
> > 
> > CSCed29590
> > Multilink PPP link flap causes output frozen for member link
> > 
> > CSCin55432
> > Internally found moderate defect: Resolved (R)
> > Spurious memory access at vipmlp_change_primary
> > 
> > 
> > On Thu, Mar 24, 2005 at 06:01:48AM -0800, David Barak wrote:
> > > 
> > > --- Lawrence Wong <lawrencewong72 at yahoo.com> wrote:
> > > <questions regarding MLPPP>
> > > 
> > > Cisco MLPPP mostly works, but there are a couple of
> > > really bad gotchas.  My experience with it is watching
> > > it NOT work on 75xx series routers.  More accurately,
> > > it would work, but when a T1 would bounce and recover,
> > > a show command would cause the router to reload.  That
> > > was not resolved as of last October (when I left the
> > > company which had the case open).
> > > 
> > > My overall impression is that MLPPP is relatively
> > > flaky.  I could recommend MLFR for point-to-point
> > > circuits, but that can be kind of flaky too (lots of
> > > problems in initial code releases), although I've now
> > > got some customers using this, and it's working most
> > > of the time.
> > > 
> > > Do you own both ends of the circuit?
> > > 
> > > -David Barak
> > > need Geek Rock?  Try The Franchise!
> > > http://www.listentothefranchise.com
> > > 
> > > 
> > > 		
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> > > http://www.yahoo.com/r/hs
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> 
> ******************************************
> Richard J. Sears
> Vice President         
> American Internet Services                          
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