Hi Lars,
-----邮件原件-----
发件人: Eggert, Lars [mailto:lars(_at_)netapp(_dot_)com]
发送时间: 2014年1月10日 16:48
收件人: Xuxiaohu
抄送: IETF; mpls(_at_)ietf(_dot_)org
主题: Re: Last Call: <draft-ietf-mpls-in-udp-04.txt> (Encapsulating MPLS in UDP)
to Proposed Standard
Hi,
that sounds good. What congestion control are you going to be specifying for
your tunnel?
IMHO, this is a common issue with any other encapsulations for MPLS and even
other applications of UDP tunnels . Of course, the following text could be
added if we believe it's necessary:
"...applications that uses the encapsulation as specified in this
document SHOULD monitor the packet loss rate to ensure that it is
within acceptable parameters. Packet loss is considered acceptable
if a TCP flow across the same network path under the same network
conditions would achieve an average throughput, measured on a
reasonable timescale, that is not less than that of the MPLS-in-UDP flow.
The comparison to TCP cannot be specified exactly, but is intended as
an "order-of-magnitude" comparison in timescale and throughput.
In essence, this requirement states that it is
not acceptable to deploy an application using the encapsulation
specified in this document on the best-effort Internet, which
consumes bandwidth arbitrarily and does not compete fairly with TCP
within an order of magnitude. One method of determining an
acceptable bandwidth is described in [RFC3448]. "
Best regards,
Xiaohu
Lars
On 2014-1-10, at 4:46, Xuxiaohu <xuxiaohu(_at_)huawei(_dot_)com> wrote:
Hi Lars,
Thanks a lot for your comments.
I wonder whether the following modified text for Congestion Consideration
section is OK from your point of view:
Since the MPLS-in-UDP encapsulation causes MPLS packets to be forwarded
through "UDP tunnels", the congestion control guidelines for UDP tunnels as
defined in Section 3.1.3 of [RFC5405] SHOULD be followed. Specifically, MPLS
can carry a number of different protocols as payloads. When the payload
traffic
is IP-based and congestion-controlled, the UDP tunnel SHOULD NOT employ its
own congestion control mechanism, because congestion losses of tunneled
traffic will already trigger an appropriate congestion response at the
original
senders of the tunneled traffic. When the payload traffic is not known to be
IP-based, or is known to be IP-based but not congestion-controlled, the UDP
tunnel SHOULD employ an appropriate congestion control mechanism.
Furthermore, because UDP tunnels are usually bulk-transfer applications as far
as the intermediate routers are concerned, the guidelines as defined in
Section
3.1.1 of [RFC5405] SHOULD apply.
Best regards,
Xiaohu
-----邮件原件-----
发件人: mpls [mailto:mpls-bounces(_at_)ietf(_dot_)org] 代表 Eggert, Lars
发送时间: 2014年1月8日 18:22
收件人: IETF
抄送: mpls(_at_)ietf(_dot_)org
主题: Re: [mpls] Last Call: <draft-ietf-mpls-in-udp-04.txt>
(Encapsulating MPLS in UDP) to Proposed Standard
Hi,
On 2014-1-2, at 16:14, The IESG <iesg-secretary(_at_)ietf(_dot_)org> wrote:
- 'Encapsulating MPLS in UDP'
<draft-ietf-mpls-in-udp-04.txt> as Proposed Standard
this document needs to describe how it addresses the issues raised in
BCP145 (RFC5405). It already contains some text about messages sizes
and congestion considerations, which is great. Unfortunately, the
text about congestion considerations is not fully in line with RFC5405.
Lars