[c-nsp] ASR920 vs ME3600 (BDI/vlan/dot1q subints)

[Mark Tinka]

On 11/May/16 08:32, CiscoNSP List wrote:

> (Apologies if double post, sent this earlier, but it hasnt shown up)
>
>
> Hi everyone,
>
> First real look at an ASR920 (Historically we have used ME3600's for this role...cust VRFs etc) - Now, I see the ASR920 is definitely "different" to the ME3600....ie. no "switchport" commands.....more like a router..
>
> So;
>
> On an ME3600, we would have a dot1q trunk coming from an edge L2 switch tagging customer vlans, on the ME3600 port, we would have:
>
> interface GigabitEthernet0/4
>  description DOT1QTRUNK_TO_EDGE_SWITCH_FOO
>  switchport trunk allowed vlan none
>  switchport mode trunk
>  load-interval 30
>  no cdp enable
>  service instance 15 ethernet
>   description MANAGEMENT_INT_FOR_TORSW
>   encapsulation dot1q 15
>   rewrite ingress tag pop 1 symmetric
>   bridge-domain 15
>
> Then a vlan int (15) with L3
>
> On the ASR920, we cannot do this....in the same way...

As you've now discovered, there is no "switchport" concept on the ASR920
as there is on the ME3600X/3800X.

The IP or MPLS stitch for ASR920's is the BDI interface, as opposed to
the SVI interface on the ME3600X/3800X.

>
> So, we can use BDI ints, or the old dot1q subints...
>
> bdi example...hopefully correct ??
>
> int gi0/0/23
> description DOT1QTRUNK_TO_EDGE_SWITCH_FOO
>  service instance 15 ethernet
>   description MANAGEMENT_INT_FOR_TORSW
>   encapsulation dot1q 15
>   rewrite ingress tag pop 1 symmetric
>   bridge-domain 15
>
> Then a BDI int (15) with L3
>
> Would the above be correct?

Yep, that is right.


>   And if so, are there any major limitations (QOS for example) that anyone is aware of when using BDI vs the old dot1q subint?  (On our ASR1001's, we initially used BDI Ints, but found netflow did not work "correctly", so swapped back to dot1q subints)

QoS on the ASR920 is closer to the ASR1000.

There is a little niggle when matching a class-map for simple egress
policing. You need to match a user-defined class-map, in addition to
matching class-default. If you do not include the user-defined
class-map, the configuration will be invalid.

Other than that, it all works really well.

Mark.