Re: [Time] Strong Technology Dependency

[Qin Wu <[e-mail]>]

Thanks for comments on the following proposed table or figure as follows:
Greg>MPLS-TP uses LSP ping or, though more rarely, ICMP as-is. In fact, MPLS-TP largely re-used all IP/MPLS OAM though adding some functionality, i.e. RDI, CV, and PCS.
Greg>Again, as in previous comment, MPLS-TP OAM does not present itself “different OAM technology”.

[Qin]: You are right, I realized both LSP Ping and MPLS-OAM use MPLS technology while ICMP uses IP technology. I will fix this in the update.

Greg>should add OWAMP and TWAMP for Performance Measurement in the following table

[Qin]: Agree.

Greg>Echo(Ping) in fact belongs continuity check.

[Qin]: Agree.

Greg>Echo(Ping) does not provide CV as IP is connectionless and has no definition of Misconnection defect.

[Qin]:Not sure about this. RFC7276 said LSP Ping is used for end-to-end
  Connectivity Verification between two LERs.
Therefore I think  IP Ping can also provide CV, what am I missing?

Greg>Actually can be used for BW, Delay and Loss measurement, though very rough.

[Qin]: Agree and will add this into the  following table.

Greg>Not, BFD and BFD Echo do not provide CV for the same reason as for ICMP – do definition of Misconnection defect. Besides, BFD Echo doesn’t work for multi-hop case but only for single hop.

[Qin]: Not sure about this. RFC7276 said SP Ping is used for end-to-end
  Connectivity Verification between two LERs.
Since BFD Echo is similar to LSP Ping, I think BFD Echo also can provide CV.

Greg>LSP Ping provides Continuity Check too

[Qin]: Agree.

Greg>All MPLS-TP OAM applicable to IP/MPLS as well

[Qin]: Agree.
Greg>MPLS-TP provides CC through use of BFD
Greg>MPLS-TP provides CV through use of BFD and extension  to provide Source ID.

[Qin]: Besides using BFD, is there any other way to provide CC or CV?


发件人: OPSAWG [mailto:[e-mail]] 代表 Qin Wu
发送时间: 2014年6月25日 16:06
收件人: [e-mail]; [e-mail]
抄送: [e-mail]
主题: [OPSAWG] Strong Technology Dependency

Hi, Mohamed:
Thanks for details review to problem statement draft
http://tools.ietf.org/html/draft-ww-opsawg-multi-layer-oam-00
and update I sent to you.

Regarding strong technology dependency issue,
Section 4.2 gives an address scheme  example to explain why the existing OAM mechanism has strong
Technology as follows:
“

Addressing scheme is a good example for an issue

that has a high price for being non-generic.  Ping of IPv4 and IPv6

looks different in the addressing scheme as well in the ICMP

indication field, but they have the same OAM functionalities.
”
You asked to clarify the exact point of this paragraph.
I think what this paragraph said is
For IP ping, IPv4 Ping protocol [RFC792] and IPv6 ping protocol [RFC4443] use different IP technology but share the same OAM function.

But I agree with you address scheme is not a typical example for strong technology dependency.
I think the typical example is ICMP, LSP Ping and MPLS-TP OAM are using different network technology but share the same OAM
functionality, i.e., Path Discovery.  Another example is ICMP,BFD,LSP Ping and MPLS-TP OAM are using different network technology but share
the same functionality, i.e., continuity check.

The following figure shows common OAM functionalities shared by various existing OAM protocols.
   |--------+-----------+--------------+--------------+------------+
   |        |Continuity |  Connectivity|    Path      | Performance|
   |        |  Check    |  Verification|  Discovery   | Monitoring |
   +--------+-----------+--------------+--------------+------------+
   |        |           |              |              |            |
   | ICMP   |           |   Echo(Ping) |  Traceroute  |            |
   |        |           |              |              |            |
   +--------+-----------+--------------+--------------+------------+
   |        |           |              |              |            |
   | BFD    |  BFD      |   BFD Echo   |              |            |
   |        | Control   |              |              |            |
   +--------+-----------+--------------+--------------+------------+
   | LSP    |           |              |              | - Delay    |
   | Ping   |           |   Ping       |  Traceroute  | - Packet   |
   |        |           |              |              |    Loss    |
   +--------+-----------+--------------+--------------+------------+
   |        |           |              |              |            |
   | IPPM   |           |              |              |            |
   |        |           |              |              |            |
   |--------+-----------+--------------+--------------+------------+
   | MPLS-TP|           |              |              |            |
   | OAM    |  CC       |   CV         |  Traceroute  | -Delay     |
   |        |           |              |              | -Packet    |
   |        |           |              |              |   Loss     |
   +--------+-----------+--------------+--------------+------------+

Hope this clarifies.

Regards!
-Qin

发件人: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]]
发送时间: 2014年6月24日 22:13
收件人: Qin Wu
主题: RE: Unified oam BOF proposal request in IETF 90

Hi Qin,

Please find attached a first set of comments.

Cheers,
Med