Re: bridged vlan interfaces

On 11/17/07 15:17, Jonathan Thibault wrote:
> I managed to get rid of the SRW2024, so now my network looks like 
> this:
> 
> (40xSM)<-T->(AP)<-T->(BH)<-T->o
> (20xSM)<-T->(AP)<-T->(BH)<-T->o
> (30xSM)<-T->(AP)<-T->(BH)<-T->o(PlainSwitch)o<-T->(in.2-br0-out)<-P->(gateway)
>             ...               o             o<-T->o(SRW208)o(mgmt)
>        (SRW208)o<-T->(BH)<-T->o
> 
> The The SRW208 are just there to put some equipment that doesn't 
> speak vlan onto the right vlans, so they couldn't affect the groups 
> of subscriber modules.

*nod*

> The exact same customers exhibit the exact same problem when I add, 
> say in.4 to the bridge.  Again, I haven't actually enabled vlan4 on 
> anything but the linux box.  APs and SMs only have vlans 1 and 2 
> configured.  BackHauls do not even understand vlans at all, they're 
> just ethernet bridges.  Yet when I add in.4 or in.3 to the bridge, my 
> phone rings.

<Heavy Sigh>  (Obviously)  Something is wrong here.

Do you have another physical interface in your Linux bridge?  I'm 
starting to wonder if there is not something odd about the configuration 
that you have (unintentionally) not portrayed.  If you have another 
interface other than in and out, try adding it (say eth2) to the bridge.

> Doing a 'tcpdump -i in.2 -n ether host <mac-of-customer>' shows me a 
> string of arp requests and replies for the gateway but practically no 
> other traffic.  Then, I 'brctl delif br0 in.4' and traffic 
> instantaneously flows, and the customer says their internet is back.

Is Spanning Tree (Protocol) (a.k.a. STP) turned on on br0?  I feel like 
there is something else going on here.

> I'll have other customers happily surfing away through the whole 
> process, this only affects some of them.  I've noticed no 
> similarities in MAC addresses, and they all run on identical 
> equipment to that of working customers (same firmware, etc.)

Do your tests reliable / predictably effect the same customers?  Are you 
sure that there is not any thing on the customers equipment that is 
messing with things?  If you provided the customer equipment (part of 
your service agreement?) can you trade out the equipment for testing and 
/ or an ""upgrade to facilitate growth of the network?

> Since I'm only using plain switches now, I can't easily 'sniff' 
> traffic beyond the linux box until I build myself some sort of 
> portable little bridge box that I could place at different points on 
> the network, so if you guys have any other ideas, please share.

A simple hub and a notebook with a single ethernet card and TCPDump will 
suffice just fine for testing.  Disconnect a cable between two pieces of 
equipment, connect said cable in to a hub, connect the hub to where the 
cable was originally connected.  Plug your notebook in to the hub and 
sniff away.



Grant. . . .

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