Mailing List Archive: Mpls with layer-2 in between

Mpls with layer-2 in between

Oct 12, 2020, 11:34 AM

Post #1 of 3 (625 views)

I have kind of a strange situation. Trying to figure out what to do moving
forward, and not sure what the best (or quickest) way to solve the issue.

I have a mpls cross-connect (pseudowire) between 2 sites. The link comes
up, but I can't pass any traffic.

sh mpls l2transport vc - shows the connection is up
ping mpls pseudowire x.x.x.x YY reply mode ipv4 - gives me a time-out.

The link goes from an ASR920 - Cisco 3850 ------- Cisco 3850 - ASR920

The long dashed line is a 40-gig layer-2 link between the 2 Cisco 3850
switches. Both switches run eigrp and terminate mpls links just fine; ie

interface TenGigabitEthernet1/0/4
no switchport
ip address 10.10.0.73 255.255.255.252
mpls ip
mpls label protocol ldp

ASR920 ---- 3850 ---- ASR920 pseudowires work fine. It's an issue when the
2nd 3850 comes into the mix.

When I do a traceroute from end-to-end, I see the vlan 1 interface of the
3850, not the loopback interface. So, I'm guessing it's taking the layer-2
path instead of using the loopback interfaces and routing it.

The best way to fix it is to remove the 3850s from the equation and put in
real routers. Unfortunately that means I can't utilize the 40 gig link to
the other site.

Is it possible to have a layer-2 connection in-between 2 mpls speaking
routers? ie

ASR920 --- 'new' router --- 3850--------3850 -- 'new' router ---- ASR920

Or, is there a way to tell the 3850s to route the connection instead of
switch it (and not break switching on them)?

Thanks
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Re: Mpls with layer-2 in between [ In reply to ]

fordlove at gmail

Oct 12, 2020, 11:48 AM

Post #2 of 3 (625 views)

Permalink

On the 3850, can you do something like:

mpls ldp router-id Loopback0

would probably take bouncing all the ldp neighbors for it to take effect.

On Mon, Oct 12, 2020 at 12:38 PM Shawn L <shawn@rmrf.us> wrote:

> I have kind of a strange situation. Trying to figure out what to do moving
> forward, and not sure what the best (or quickest) way to solve the issue.
>
> I have a mpls cross-connect (pseudowire) between 2 sites. The link comes
> up, but I can't pass any traffic.
>
> sh mpls l2transport vc - shows the connection is up
> ping mpls pseudowire x.x.x.x YY reply mode ipv4 - gives me a time-out.
>
> The link goes from an ASR920 - Cisco 3850 ------- Cisco 3850 - ASR920
>
> The long dashed line is a 40-gig layer-2 link between the 2 Cisco 3850
> switches. Both switches run eigrp and terminate mpls links just fine; ie
>
> interface TenGigabitEthernet1/0/4
> no switchport
> ip address 10.10.0.73 255.255.255.252
> mpls ip
> mpls label protocol ldp
>
> ASR920 ---- 3850 ---- ASR920 pseudowires work fine. It's an issue when the
> 2nd 3850 comes into the mix.
>
> When I do a traceroute from end-to-end, I see the vlan 1 interface of the
> 3850, not the loopback interface. So, I'm guessing it's taking the layer-2
> path instead of using the loopback interfaces and routing it.
>
> The best way to fix it is to remove the 3850s from the equation and put in
> real routers. Unfortunately that means I can't utilize the 40 gig link to
> the other site.
>
> Is it possible to have a layer-2 connection in-between 2 mpls speaking
> routers? ie
>
> ASR920 --- 'new' router --- 3850--------3850 -- 'new' router ---- ASR920
>
> Or, is there a way to tell the 3850s to route the connection instead of
> switch it (and not break switching on them)?
>
> Thanks
> _______________________________________________
> cisco-nsp mailing list cisco-nsp@puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
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Re: Mpls with layer-2 in between [ In reply to ]

shawn at rmrf

Oct 12, 2020, 11:50 AM

Post #3 of 3 (625 views)

Permalink

Unfortunately, I already have that in there, on both sides.

mpls ldp router-id Loopback0 force

But it's still trying to use the vlan1 interface

On Mon, Oct 12, 2020 at 2:48 PM Scott Miller <fordlove@gmail.com> wrote:

> On the 3850, can you do something like:
>
> mpls ldp router-id Loopback0
>
> would probably take bouncing all the ldp neighbors for it to take effect.
>
> On Mon, Oct 12, 2020 at 12:38 PM Shawn L <shawn@rmrf.us> wrote:
>
>> I have kind of a strange situation. Trying to figure out what to do
>> moving
>> forward, and not sure what the best (or quickest) way to solve the issue.
>>
>> I have a mpls cross-connect (pseudowire) between 2 sites. The link comes
>> up, but I can't pass any traffic.
>>
>> sh mpls l2transport vc - shows the connection is up
>> ping mpls pseudowire x.x.x.x YY reply mode ipv4 - gives me a time-out.
>>
>> The link goes from an ASR920 - Cisco 3850 ------- Cisco 3850 - ASR920
>>
>> The long dashed line is a 40-gig layer-2 link between the 2 Cisco 3850
>> switches. Both switches run eigrp and terminate mpls links just fine; ie
>>
>> interface TenGigabitEthernet1/0/4
>> no switchport
>> ip address 10.10.0.73 255.255.255.252
>> mpls ip
>> mpls label protocol ldp
>>
>> ASR920 ---- 3850 ---- ASR920 pseudowires work fine. It's an issue when
>> the
>> 2nd 3850 comes into the mix.
>>
>> When I do a traceroute from end-to-end, I see the vlan 1 interface of the
>> 3850, not the loopback interface. So, I'm guessing it's taking the
>> layer-2
>> path instead of using the loopback interfaces and routing it.
>>
>> The best way to fix it is to remove the 3850s from the equation and put in
>> real routers. Unfortunately that means I can't utilize the 40 gig link to
>> the other site.
>>
>> Is it possible to have a layer-2 connection in-between 2 mpls speaking
>> routers? ie
>>
>> ASR920 --- 'new' router --- 3850--------3850 -- 'new' router ---- ASR920
>>
>> Or, is there a way to tell the 3850s to route the connection instead of
>> switch it (and not break switching on them)?
>>
>> Thanks
>> _______________________________________________
>> cisco-nsp mailing list cisco-nsp@puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-nsp
>> archive at http://puck.nether.net/pipermail/cisco-nsp/
>>
>
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