[bess] Review on draft-ietf-bess-evpn-yang-06

[Yu Tianpeng <[e-mail]>]

Dear authors and WG,
I had a review on draft-ietf-bess-evpn-yang-06.
This draft covers most of the evpn/vpws scenarios, but there are some
points I would like to discuss.

For small points that do not impact the architecture of the yang data
model, I have made changes in a new yang file directly (attached), which
will be easier to understand.
Also, some comments related to the structure of the data model in the final.
Appreciate authors and WG can have a review on comments and proposed
changes below.
Thanks in advance.
Regards,
Tim
=================================================================================
Changes:
ietf-ethernet-segment.yang
1. esid-type defined. current uint32 cannot cover 10 octs ESI. We can
either use a string with a regex or uint64 with a range. in the attachment
is the regex.
2. change key to esi instead of "name", the name looks like a string or a
description to me, cannot be used as the key.
3. add new leaf "interface" to indicate which ESI applied to which
interface.
4. BGP parameters are deleted, I don't think RD RT are concepts related
with ES. I have put a new leaf es-list in the EVPN yang data model
providing links between ES and EVPN yang
5. change of VLAN type to unit16 with range limit

ietf-evpn.yang
1. evpn label mode function added
2. re-write RD RT part as rt-types:vpn-route-targets is a list type
already, an extra level of list definition in EVPN is not needed anymore.
3. ES list leaf added. This leaf provides a list indicating ESs bound to
the EVPN instance.
4. control word and MTU added
5. statistics part re-structure.
6. change the counter type from uint32 to counter64 to avoid overflow.
7. interface type leaf added, the previous vpws-vlan-aware deleted. reason:
all interface type should be covered across EVPN and VPWS

General comments:
1. In EVPN yang, I would suggest to re-structure current content as below
instead of one evpn container :
- EVPN general: RD, RT, name, etc.
- EVPN ELAN/VPWS/E-TREE specifics: BUM, leaf indication, proxy.. and use
the generals to get yang data model for each scenario.

2. EVPN parameters are not registered under /ni:network-instances and /pw:
pseudowires. Now only very few info registered