[c-nsp] Cisco Nexus as MetroE switch?

[Marian Ďurkovič]

On Wed, Nov 04, 2015 at 11:04:46AM +0000, Adam Vitkovsky wrote:
> Hmm maybe Huawei s doing something radically different.

Their implementation follows RFC6325.

> But my understanding is that TRILL is using MAC in MAC encapsulation just
> like PBB.

Well, there must be two MAC headers if you want to transport ethernet packet
inside a container over ethernet network, but similarities with PBB end here.
TRILL introduces its own header with similar information like IP header
(source/destination addresses, TTL, various flags, maybe options).
Although TRILL header is smaller and optimized for fast ASICs (for example 
addresses have only 2 bytes to allow faster lookups), TRILL switches *route*
packets the same way as IP routers do - each hop has its own routing table 
(created dynamically by IS-IS) and makes independent decisions about next hop
for each packet (with per-flow loadsharing over multiple equal-cost paths).
They also decrement TTL and change outer MAC addresses on each hop, perform
RPF check for multicast frames etc.


   With kind regards,

       M.