Re: [Time] [OPSAWG] Strong Technology Dependency

I think one problem here is over-use of the word "connectivity". Aren't 
you really testing for reachability?

Tom Taylor

On 30/06/2014 3:39 AM, Qin Wu wrote:
> 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:opsawg-bounces@ietf.org] 代表 Qin Wu
> 发送时间: 2014年6月25日 16:06
> 收件人: time@ietf.org; opsawg@ietf.org
> 抄送: mohamed.boucadair@orange.com
> 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: mohamed.boucadair@orange.com<mailto:mohamed.boucadair@orange.com> [mailto:mohamed.boucadair@orange.com]
> 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
>
>
>
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