From: Joe Chang (changjoe@earthlink.net)
Date: Fri Feb 14 2003 - 12:26:10 GMT-3
----- Original Message -----
From: "Pang Gery" <pang_gery@yahoo.com.hk>
To: <ccielab@groupstudy.com>
Sent: Thursday, February 13, 2003 8:43 AM
Subject: QoS need confirm-- a bit long
> Hi Group,
>
> I have just reviewed the QoS part and make the following brief notes. My
focus is on whether the feature take effect with and without congestioin.
Could you please help to review and correct me if my concept is wrong?
>
> 1.1 Policy-based routing and QoS via BGP
>
> They just classify packets, will not drop packet, and take effect with
and w/o congestion.
>
Policy based routing has the option of dropping packets. Qos propagation via
BGP only assigns IP precedence values to certain packets and does not have
the option of dropping packets.
> 1.2 CAR
>
> It can classify and drop packet, and take effect with and w/o
congestion.
>
That's right.
> 2.1 Priority Queue / Custom Queue Ip RTP / FR RTP / CBWFQ / LLQ
>
> Take effect only when congestion.
>
> 2.2 Question: is the bandwidth command used in policy-map of CBWFQ same
as the priority command used in LLQ?
>
> My feeling is the bandwidth is used for data and priority is used
for real-time traffic like voice. Also, bandwidth sets the minimum amount
allocated for 'that traffic' at congestion, when there is no congestion,
'that traffic' can use more available bandwidth.
>
> However, the priority command guarantee the maximum resources for
specific traffic whether there is congestion or not.
>
There was a thread on this list about wheter the priority queue in LLQ is
active even when there is no congestion. Does anyone remember if this debate
was resolved?
> 3. GTS / FRTS
>
> They are not congestion management and will do the shapping with or
without congestion.
>
> Am I right?
>
That's right, the goal of traffic shaping is to stay within the capacity of
downstream devices.
> Thank you very much.
>
> Gery Pang
>
>
>
> Yahoo! =l)G/d(%+H=c .I$U<i,y$h&V
> http://voicemail.yahoo.com.hk
This archive was generated by hypermail 2.1.4 : Sat Mar 01 2003 - 11:06:23 GMT-3