From: Mike Williams (ccie2be@swbell.net)
Date: Wed Oct 08 2003 - 19:15:49 GMT-3
Not neccesarily true... If you use GTS on an interface, then (AFAIK) it
will only kick in when there is congestion, but if you apply shaping
using a policy map (i.e. class-based shaping), the shaping "creates a
false congestion" whenever the that traffic class exceeds the values you
use on the shaping command (this was told to me by a group of Cisco
SE's) and then actively shapes the traffic. I configured the policy to
shape certain traffic down to 8Kbps, and it works like a charm
regardless of whether the interface was congested or not. Furthermore,
my testing was also done on an ethernet interface, and this was a 3600
router (not really "high-end"). In my testing, we were trying to limit
the bandwidth used by a VPN tunnel. Since we knew the IP address of
each endpoint, I just made an access-list, made a class that matched
that ACL, then made a policy that only affected that class. Since you
can only shape on traffic going out of an interface, I had to apply this
shaping to the FastEthernet interface (instead of the ATM interface).
Like I said, it worked like a charm, and I could see that it was
actively shaping the traffic down to 8Kbps, as well as how many packets
were delayed, dropped, etc...
Mike W.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
asadovnikov
Sent: Wednesday, October 08, 2003 5:51 AM
To: 'Hunt Lee'; ccielab@groupstudy.com
Subject: RE: Which one should I pick ?
The way you put the question makes policing the only choice. Either a
police statement as you specified, or older CAR will do. Shaping only
kicks in during congestion periods and is not in effect unless a
congestion is present.
Further I do not believe shaping is supported on Ethernet (some higher
end boxes to have additional QOS implemented in hardware).
Best regards,
Alexei
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Hunt Lee
Sent: Tuesday, October 07, 2003 10:06 PM
To: ccielab@groupstudy.com
Subject: Which one should I pick ?
If I have a question:
Configure CBWFQ on R1's Ethernet interface such that it allocates min
bandwidth of 3mbps for VLANA. VLANA traffic should limit to 5mbps and
cannot utilize more physical bandwidth during non-congestion period.
Should I use:
policy-map cbwfq
class VLAND
bandwidth 3000
shape peak 5000000
OR
policy-map cbwfq
class VLAND
bandwidth 3000
police 5000000 937500 1875000 conform-action transmit exceed-action
drop violate-action drop
And if you could give me reasoning on why you pick that one, it would be
greatly appreciated.
Thank you so much in advance,
H.
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