Subject: [ippm] comments on draft-deng-ippm-wireless

From: "MORTON, ALFRED C (AL)" <[email-masked]>
Date: Mon, 3 Mar 2014 07:44:50 -0500

IPPM,

comments on draft-deng-ippm-wireless

In section 2:

Under Dynamic Load Balancing:

   Figure 1: Active Measuring Traffic versus Actual Traffic in case of
                              Device Pooling

   Hence, under such environments, if active performance measurement
   methods[RFC4656][RFC5357] are employed, the injected bogus data
   traffic may traverse along a different path to the one used by the
   targeted traffic or even interfere with them due to the subtle nature
   of wireless-involved links (as explained in the next subsection).
... 

Later, under congestion detection:
   o  almost all the time, the wireless "last mile" would be the
      bottleneck of end-to-end service quality.

Points: 
 * The active traffic sent at different times will be traversing 
different paths in Fig 1, just like the load-balanced user traffic through the
pools of SGSN and GGSN.

 * Since the wireless link usually determines the overall dataplane
performance, an active and passive measurement from the same location
yield very similar results.

There may be other reasons to prefer active or passive techniques,
but the discussion in section 2 doesn't make a clear case for passive-only.

regards,
Al

---

From: lingli deng <[email-masked]>
Date: Fri, 14 Mar 2014 09:09:31 +0800

Hi Alfred,

Thanks for your comments.
It is really nice for you to read it through in such careful way.
However, the usecases are meant to be interpreted independently.
Yes I agree that, under most cases, since the wireless is likely to be the
bottleneck, pooling would not matter much.
But that would not exclude the necessity of passive measurement for pooled
devices, since something unusual happeded on the wired part is actually
what we might be able to take immediate measures to respond.

Lingli

MORTON, ALFRED C (AL) <[email-masked]>于2014年3月3日星期一写道：
> _______________________________________________
> ippm mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/ippm
>

-- 
邓灵莉/Lingli Deng
中国移动通信研究院/China Mobile Research Institute
e-mail: [email-masked]
tel: 15801696688-3367
mobile: 13810597148

---

From: lingli deng <[email-masked]>
Date: Fri, 14 Mar 2014 19:31:52 +0800

Hi Alfred,

Lingli