[c-nsp] VSS1440 to ASR1002 - MEC issues

Sun May 3 23:23:28 EDT 2009

No, they are not right but since you have configured the main port
channel as a L3 interface, and that's not supported ( that's what I
meant by only VLANS), anything can happen from ASR1000 perspective

HTH

> 
> 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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