Hi,
Consider uA advertisement(these examples are from the draft, similar line of 
argument applies to uDt as well)
2001:db8:0:0N00:FNAJ

Generally, it is optimal to download following route, as it avoids double 
lookup/packet-re-circulation within the same node.
2001:db8:0:0N00:FNAJ::/80(This route has both node and function components in 
it)

However, the draft also recommends downloading following route:
2001:db8:0:FNAJ::/64(This route does NOT have node component in it)

I guess this route is required if during compression, an uA SID gets split into 
two separate micro-SID-containers
Say, the DA has:
2001:db8:0:A00:B00:C00:D00:N00
SRH has
2001:db8:0:FNAJ::

Or, maybe for a packet is sent from a controller, maybe it wants to sent just 
the uA SID for the first-hop router
2001:db8:0:FNAJ:M00:

However, we think both these use-cases are not important enough.
Also, the advertisement of uA/uDt are inclusive of the node-part,
(i.e. uA SID is 2001:db8:0:0N00:FNAJ and not just 2001:db8:0:FNAJ) it doesn't 
make sense for a compressing router to split the SID itself onto two different 
containers.

One more very strong case, not to allow scenarios that might require a router 
to program this route:
2001:db8:0:FNAJ::/64

If this is disallowed, and we always program uA/uDt SIDs along with the 
node-part, then, we can have many more local-SIDs available on a NODE.
Instead of LIB space being per block, it becomes per-locator.
If we use  this method, a router can just use one more locator from the same 
block and start advertising local SIDs from that locator:
For e.g.
2001:db8:0N00:FNAJ::
And
2001:db8:0N01:FNAJ::
Can be advertised from the same router.
This has the great multiplier effect of number of local locators on a node.(If 
a node uses two different locators, the number of micro-SIDs doubles from 
around 8k to around 16k)

Can you please share your thoughts on this?

Thanks, and regards,
Bharath R.

Juniper Business Use Only

_______________________________________________
spring mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/spring

Reply via email to