Hi Steven,
couple of suggestions.
this is strange behavior - normally a router doesn't know the difference
between a IP/ICMP/UDP/TCP packet when it's switching, unless you are
doing NAT or ACLs or something along those lines. we are just
going to switch based on the destination address. so the behavior
you are seeing is definitely strange. one thing to note about the
code are you are running - 12.0(2)XE1 - is the first generation of a
bleeding edge code.
you could not run bridged services in 12.0(13)S as the "p" image -
service provider feature set - does not include any bridging functionality.
i would recommend running latest 12.1 mainline code to pick up various
bug fixes - 12.1(5) - if it's already available - if you want
to keep your existing config.
one feature you may want to keep in mind to migrate your users to is
RBE - Route Bridge Encapsulation - first introduced in 12.1(2)T.
this allows you to scale bridged services better as we do away with IRB
and virtual interfaces. we basically strip the bridge header off the
incoming atm pvc, and treat it as a routed packet.
----you have spanning tree disabled. if you have a looped PVC anywhere in your router, you can cause a broadcast storm, packet storm etc, due to packets looping endlessly. when you are seeing this connectivity issue, do you have high traffic rates? it would probably point to a looped PVC causing a lot of broadcasts/multicasts
----
in order to troubleshoot this issue to narrow down the cause of the error, you may want to start by characterizing the problem further. it would be helpful to figure out if you have connectivity till the router when this problem occurs. if you have connectivity till the router, but not thru' the router [i.e. next hop] we might have a fast-switching issue. if you do not have connectivity to the router, but you have access thru' the router [you may be having some sort of queue wedge] if you have no connectivity at all, it could be a queue wedge, or problems in your DSL provider. one useful thing you can do is log onto the router and do per PVC atm packet debugging [just turn it on for a single VC]. any process switched packet will be picked up by the debugs. you can then look at what is happening to your traffic. there is probably a lot more that we can discuss in terms of troubleshooting steps. i would suggest opening a case with the cisco TAC to get further suggestions, troubleshooting advice/help and more research.
regards .siva
> > I am haveing some strange issues with ADSL service provisioned on a > 7206 with a PA-A3 ATM interface. > > Router: 7206 (non VXR) > IOS: 12.0(2)XE1 > ATM interface: PA-A3 Hardware rev 2.0 > > Below I have an example of a typical configuration that we have been > using now for about 9 months. It is a fairly simple bridged, non PPP > configuration. It has been working well for us up until about a week > or so ago. Since that time customers have complained of periodic and > fairly brief outages. I have been able to reproduce the problem on my > own DSL circuit, but the exact symptoms are very inconsistant. At > times it seems that I have only partial connectivity. Specifically, I > can not pass any UDP traffic, so I can't traceroute to a remote site, > and I can't do DNS lookups, but I can ping or make TCP connections to > the remote site. At other times I loose IP connectivity completely. > > There are no errors recorded on the PA-A3 interface. In fact I see no > errors anyplace. The ATM subinterface stays up and shows packets > comming and going. The bridge table seems to remain in tact. It is > kind of like the bridged to routing mechanism breaks. > > In an attempt to fix the problem, I have tried to upgrade the IOS on > the router to 12.0(13)S. However, with that IOS, the ADSL config > doesn't work at all. All of the interfaces look fine, the bridge looks > okay, but absolutely no IP connectivity what-so-ever. We are also > using the PA-A3 for a number of frame-relay circuits and they work > fine in either IOS. I have heard no complaints from any of those > customers. > > So my questions are: > > 1. Is there any idea what is causing the periodic outages? > > 2. Why with the 12.0(13)S IOS does the ADSL configuration not work at all. > > > Below is a typical configuration for the ADSL service. Am I missing > something that is causing one of the problems listed above. > > Thanks for your help > > > bridge 2 protocol ieee > bridge 2 route ip > > > interface ATM6/0.3001 point-to-point > mtu 2048 > no ip directed-broadcast > no ip proxy-arp > no ip mroute-cache > atm pvc 3001 3 35 aal5snap 1536 1536 > bridge-group 2 > bridge-group 2 spanning-disabled > > > interface BVI2 > mtu 3000 > ip address 206.53.96.18 255.255.255.252 > no ip directed-broadcast > > > -- > ================================================================== > Steven Saner SouthWind Internet Access, Inc. > ssaner@southwind.net Systems/Network Administrator > http://www2.southwind.net/~ssaner http://www.southwind.net > 263-7963 Wichita (800)525-7963 >
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