[c-nsp] VSS1440 to ASR1002 - MEC issues

[Alasdair McWilliam]

Even if ASR only supports GEC, surely my apparent 'one way' traffic  
symptoms aren't right? I only have one Gigabit Ethernet link in the  
Port-Channel, between the ASR and the active chassis within the VSS.  
When the channel-group command is removed from the ASR's GE interface,  
and the config moved onto the GE interface, it starts to work a treat,  
despite the VSS still thinking it's an EtherChannel !

Also, the 'switch accept mode virtual' command was run on the active  
node when the switches were first converted to VSS and rebooted.

Many thanks
Alasdair



On 2 May 2009, at 01:43, Daniel de la Rosa (ddelaros) wrote:

> That's correct, ASR1000 GEC only support static VLAN LB at the moment
> and not LACP. So this can only work if you are ok on just using GEC  
> with
> VLANs on both sides as Tassos mentioned. Since you are deploying GEC  
> for
> redundancy, this VLAN static LB should be able to give you what you
> need. Also you need to have the VSS on GEC mode on.
>
> HTH
>
>
> -------------
> Daniel de la Rosa
> CCIE # 4622
> Technical Marketing Engineer
> ERBU, Cisco Systems
>
>
>
>>
>>
>> ASR1000 doesn't -yet- support the well-known EtherChannel/LACP. If i
>> remember right, RLS5
>> will have it.
>>
>> There is a feature called VLAN Mapping to Gigabit EtherChannel (GEC)
>> Member Links, but i
>> don't think it would help you much, since you have L3 portchannels on
>> both sides.
>>
> http://www.cisco.com/en/US/docs/ios/lanswitch/configuration/guide/ 
> lsw_c
>> fg_gecvlan.html
>>
>> --
>> Tassos
>>
>> Alasdair McWilliam wrote on 01/05/2009 18:29:
>>> Hello,
>>>
>>> I'm currently deploying two Cisco 6509-E chassis with VS-Sup720-10GE
>> (in
>>> a VSS 1440 cluster/configuration) with dual ASR 1002 routers to
>> provide
>>> aggregation of multiple upstream links (running multiple BGP and
>> EIGRP
>>> sessions).
>>>
>>> I wanted to utilize MEC between each ASR and each 6509 chassis to
>> build
>>> in as much resilience as possible. However this configuration seems
>> to
>>> be playing up and so I thought I'd ask the experts!
>>>
>>> Physical Topology:
>>>
>>> ASR Gi0/0/0 into 6509 Chassis 1 Module 1 Port 1
>>> ASR Gi0/1/0 into 6509 Chassis 2 Module 1 Port 1
>>>
>>> The ASR is running IOS-XE 2.3.0 (IOS 12.2(33)XNC) AISK9 with dual
> IOS
>>> processes.
>>> The VSS chassis are running IOS 12.2(33)SXI1 ISK9 with a 4x 10GE VSL
>> (2
>>> supervisor 10GE interfaces, 2 10GE interfaces on a 6708-10GE line
>> card).
>>> I'm just using CAT6 between the ASR and the 6748-GE-TX line cards in
>> the
>>> VSS boxes.
>>>
>>> ASR configuration:
>>>
>>> interface Port-Channel1
>>> ip address x.x.x.5 255.255.255.252
>>> ip hello-interval eigrp 100 2
>>> ip hold-time eigrp 100 6
>>> ip authentication mode eigrp 100 md5
>>> ip authentication key-chian eigrp 100 vcoresw1-chain
>>> ip summary-address eigrp 100 0.0.0.0 0.0.0.0 255
>>> no ip redirects
>>> no ip unreachables
>>> no ip proxy-arp
>>> no shut
>>> !
>>>
>>> interface Gi0/0/0
>>> channel-group 1
>>> no shut
>>>
>>> interface Gi0/1/0
>>> channel-group 1
>>> no shut
>>>
>>> Cisco VSS configuration:
>>>
>>> int Gi1/1/1
>>> no switchport
>>> channel-group 3 mode on
>>>
>>> int Gi2/1/1
>>> no switchport
>>> channel-group 3 mode on
>>>
>>> int Po3
>>> desc *** MEC to br1-po1 ***
>>> no ip redirects
>>> no ip unreachables
>>> no ip proxy-arp
>>> ip vrf forwarding edge-vrf
>>> ip address x.x.x.6 255.255.255.252
>>> ip hello-interval eigrp 100 2
>>> ip hold-time eigrp 100 6
>>> ip authentication mode eigrp 100 md5
>>> ip authentication key-chain eigrp 100 br1-chain
>>> no shut
>>> !
>>>
>>>
>>>
>>> The problem I am experiencing seems to be one way traffic between
> the
>>> VSS cluster and the Border Router. Pinging across this /30 subnet
>> does
>>> not work in either direction. EIGRP relationships build when the Po
>>> interfaces first come online and then immediately time out moments
>>> later. The VSS cluster then does not see any further EIGRP traffic
>> from
>>> the ASR. However the ASR seems to think it's successfully building
> an
>>> adjacency to the VSS. However this times out due to 'retry limit
>>> exceeded' every minute or so, but seems to think it re-establishes
>> again.
>>>
>>> This problem persists if we drop the PortChannel to just one Gigabit
>>> Ethernet interface. The second interface can be shut down or
> actually
>>> removed from the Po config (eg. no channel-group 1).
>>>
>>> The really interesting thing is, with one link, if we remove the
>>> channel-group comand from the one remaining ASR interface, all of a
>>> sudden the link springs to life. Pings between the ASR Gi0/0/0
>> interface
>>> and the Po3 VSS interface are successful. EIGRP relationship comes
> up
>>> immediately and is stable, and routes are exchanged as you'd expect.
>>>
>>> How does this work? With the ASR thinking it's a non-etherchannel
>>> interface, but the VSS thinking it IS an EtherChannel (with 1
>> member),
>>> surely it should just fail?
>>>
>>> Am I doing something wrong or could this be a bug in either VSS or
>> the ASR?
>>>
>>> It's not earth shattering, we could just configure 2 EIGRP sessions
>>> between the VSS and the ASR (4 in total with 2 ASRs) but don't think
>>> this is as clean an implementation as MEC across fully redundant
>> chassis
>>> and line cards (one of the big selling points of the VSS !!)
>>>
>>> Any help would be much appreciated!
>>>
>>> Thanks
>>> Alasdair
>>>
>>>
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