[c-nsp] Cisco Nexus as MetroE switch?

[Justin M. Streiner]

On Sat, 17 Oct 2015, Mark Walters wrote:

> The 5548/5596 fits that physical requirement, but those have a limited
> feature set with no actual E-line features.
>
> In small PoPs we¹ve used those as simple 1/10G layer2 aggregation switches
> fronted by PEs with E-line features, like ME3600s.
>
> One big caveat in that setup: the N5ks consider MPLS-tagged traffic to be
> ³non-IP², for which the only etherchannel hashing is ³src-dst-mac².  So
> one link in a 4x10G etherchannel can get slammed while the others are
> idle.  We worked around by creating multiple(/parallel) layer3 peerings
> between some devices and manually setting the MAC address on the SVIs to
> influence the hashing decision.  Annoying.

Also, be aware that the Nexus 5500 platform uses cut-through switching to 
decrease latency in its intended application (data centers).  In other 
applications such as building aggregation or metro-E networks, that can 
cause some troubleshooting headaches.

For example, if one port starts receiving bad frames for whatever reason, 
those bad frames will be forwarded, because the switch starts forwarding 
as soon as it receives the header information.  This can cause several 
ports (depending on VLAN, destination MAC addresses, etc) to show output 
errors, or the adjacent devices to show input errors on the interfaces 
that connect to the Nexus 5K.  Your ops folks need to be aware of this
behavior and know to start their troubleshooting at whichever port on the
Nexus 5K has inbound errors, not all of the ports that show outbound 
errors, or the ports on the adjacent devices that show inbound errors.

jms

> On 10/14/15, 5:52 PM, "cisco-nsp on behalf of Gavin McBride"
> <cisco-nsp-bounces at puck.nether.net on behalf of gavmcb.lists at gmail.com>
> wrote:
>
>> Hello all,
>>
>> I've been evaluating a few platforms for a smallish MetroE-style
>> deployment, focused on E-Line services between a number of sites, with n x
>> 10G DWDM links between sites.
>>
>> Looked at the usual suspects e.g. Cisco ME3600X/ME3800X, ASR920, as well
>> as
>> Juniper EX4550 and QFX5100.
>>
>> What I am after is a platform that will give me a bunch (32-40 odd) 1G/10G
>> capable SFP+ ports, no need for 40G/100G, and due to starting off
>> smallish,
>> probably looking more at a 1RU/2RU box rather than a chassis based
>> solution
>> (so no ASR9000 at this point).
>>
>> Cisco have just pointed to their Nexus 9000 switches however, which has me
>> a little surprised. From looking at their website, they really look like
>> something aimed at a more Enterprise/Data Centre role, and I can't help
>> but
>> get the feeling they are trying to shoehorn any product in to suit the
>> role
>> I'm describing.
>>
>> Is anybody else out there using these in such a role, or able to comment
>> on
>> the suitability of such a switch?
>>
>> Also, how do people feel about using NX-OS and VXLAN vs. IOS and IP/MPLS?
>>
>> Thanks in advance.
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