[186112] in North American Network Operators' Group
Re: EoMPLS vlan rewrite between brands; possibly new bug in Cisco IOS
daemon@ATHENA.MIT.EDU (Jonas Bjork)
Fri Nov 27 23:55:08 2015
X-Original-To: nanog@nanog.org
From: Jonas Bjork <mr.jonas.bjork@me.com>
In-reply-to: <CAAWx_pW8XjrX6Ldt+6EXGntRRUsda5v56yZBSxe-HAcbs+FBAg@mail.gmail.com>
Date: Sat, 28 Nov 2015 05:55:01 +0100
To: James Bensley <jwbensley@gmail.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
Dear Mr. Bensley,
The platform is Cisco 7600 on side A and HP A5500-HI on side B. I am =
currently running IOS v12.2-33.SRE5 and I'm trying to upgrade to =
v15.3-3.S6.
In the current version the VC type is Eth VLAN and I have tried all =
different options on the HP side with no success. On the Cisco side I =
don't know if there is anything I can do - the negotiation seems to take =
place without any possible user interference.
It's true that I can terminate the tunnel elsewhere and switch the =
traffic using layer 2 but I don't want to have any "ugly" solutions in =
the network. Everything works fine even though I rewrite the vlan id =
(and that is essential for my solution) at the moment and it bothers me =
that an IOS upgrade triggers this bug. The bug is submitted (against =
Juniper) as previously mentioned in this thread but Cisco won't do =
anything about it.
Best regards,
Jonas Bjork
Network Nerd
> On 16 Nov 2015, at 10:21, James Bensley <jwbensley@gmail.com> wrote:
>=20
> On 15 November 2015 at 01:31, Jonas Bjork <mr.jonas.bjork@me.com =
<mailto:mr.jonas.bjork@me.com>> wrote:
>> Dear Mr. Jeff,
>>=20
>> Thank you for your reply. Below is the complete output in question =
(l2 is short for l2transport).
>> You are mentioning platform capabilities and that the default might =
have changed. How do I alter this?
>>=20
>> pe#sh mpls l2 vc 42 d
>> Local interface: Po190.42 up, line protocol up, Eth VLAN 42 up
>> Destination address: X.X.1.89, VC ID: 42, VC status: down
>> Last error: Imposition VLAN rewrite capability mismatch with peer
>> Output interface: none, imposed label stack {}
>> Preferred path: not configured
>> Default path: no route
>> No adjacency
>> Create time: 00:00:59, last status change time: 00:31:40
>> Last label FSM state change time: 00:00:18
>> Last peer autosense occurred at: 00:00:18
>> Signaling protocol: LDP, peer X.X.1.89:0 up
>> Targeted Hello: X.X.0.2(LDP Id) -> X.X.1.89, LDP is UP
>> Graceful restart: not configured and not enabled
>> Non stop routing: not configured and not enabled
>> Status TLV support (local/remote) : enabled/not supported
>> LDP route watch : enabled
>> Label/status state machine : remote invalid, LruRnd
>> Last local dataplane status rcvd: No fault
>> Last BFD dataplane status rcvd: Not sent
>> Last BFD peer monitor status rcvd: No fault
>> Last local AC circuit status rcvd: No fault
>> Last local AC circuit status sent: DOWN PW(rx/tx faults)
>> Last local PW i/f circ status rcvd: No fault
>> Last local LDP TLV status sent: No fault
>> Last remote LDP TLV status rcvd: Not sent
>> Last remote LDP ADJ status rcvd: No fault
>> MPLS VC labels: local 242, remote 1199
>> Group ID: local 0, remote 0
>> MTU: local 9216, remote 9216
>> Remote interface description:
>> Remote VLAN id: 42
>> Sequencing: receive disabled, send disabled
>> Control Word: Off (configured: autosense)
>> SSO Descriptor: X.X.1.89/42, local label: 242
>> Dataplane:
>> SSM segment/switch IDs: 0/0 (used), PWID: 142
>> VC statistics:
>> transit packet totals: receive 0, send 0
>> transit byte totals: receive 0, send 0
>> transit packet drops: receive 0, seq error 0, send 0
>> pe#
>>=20
>> Anyone else: feel free to join in. Maybe we have any L2VC/PW ninjas =
watching.
>>=20
>> Best regards,
>> Jonas Bjork
>=20
> Hi Jonas,
>=20
> In that output you have "Remote VLAN id: 42" -What is the local VLAN
> ID on your Cisco PE? Do you need to VLAN rewrite here?
>=20
> Since you using different VLANs at each end, can you build the
> pseudowire at a point in the network stack where the VLAN tag has been
> popped off already and transport the frames untagged, so they will be
> pushed on again at the other end? (Is this is a VC type 4 pseudowire,
> check with "show mpls l2transport binding 42", if so, a dummy VLAN
> should be pushed on and popped off transparently if all hardware in
> use supports it).
>=20
> I don't know HP but with the Cisco 7600 for example, if it's VLAN 50
> then you could add "interface vlan 50; xconnecy X.X.1.89 42 encaps
> mpls", if your hardware supports that. Or use mux-uni; "int gix/x.y;
> encaps dot1q y; xconnecy X.X.1.89 42 encaps mpls". Then add vice versa
> on the HP kit.
>=20
> What IOS have you tried to upgrade to, 15.2(4)S4a? If this is a VC
> type 4 pseudowire and either the HP or Cisco isn't supporting
> inserting a dummy VLAN tag, why is this a VC type 4 pseudowire? The
> VLAN re-write I guess. Certainly in IOS 15.3 (so probably also in 15.2
> but I'm not 100% certain of that) Cisco IOS should be defaulting to VC
> type 5 unless the other end negotiates down to VC type 4. VC type 5 in
> IOS supports transporting of untagged, tagged and double tagged
> frames, I don't think there is any functionality in VC type 5 that
> wasn't in older type 4's so I'd try and work out why your devices are
> negotiating type 4 and maybe try to fix that, or as above, transport
> untagged.
>=20
> Cheers,
> James.
