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:[email protected]] 代表 Qin Wu
发送时间: 2014年6月25日 16:06
收件人: [email protected]; [email protected]
抄送: [email protected]
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: [email protected]<mailto:[email protected]>
[mailto:[email protected]]
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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