Thanks Erik,
The info you provided is usefull.Sorry I wasn’t clear on my
question. I wanted to ask more on the marking of the packets as they leave the
CE router to the PE.
So the best practice would be to mark customer packets similar to service
provider’s marking and classification of packets in their network to ensure QOS
works end to end(head end site to the remote site).
Thanks
Ramu
--- On Wed, 30/12/09, [email protected] <[email protected]>
wrote:
From: [email protected] <[email protected]>
Subject: RE: [OSL | CCIE_RS] QOS question
To: [email protected], [email protected]
Received: Wednesday, 30 December, 2009, 4:44 PM
Ramarao,
Q1-
If you specified "max-reserved-bandwidth 100" and you allocated 100% of
the bandwidth to other classes, the class-default (unclassified traffic)
would be starved and zero bandwidth would be allocated to it during
periods of congestion. When bandwidth is freed up, this residual
bandwidth will be assigned to the class-default queue and its traffic
will be transmitted.
Q2-
Class-maps are locally significant to the router. They have no bearing
on how your Service Provider treats your traffic. They are used to
identify (classify) traffic locally to be used by a policy map for
treatment (queueing, marking, etc). What IS passed to your service
provider are either your TOS or DSCP markings. The Service Provider
will look for these markings upon ingress with their own locally
significant Class-Maps for treatment within their cloud - hop-by-hop.
What you need to do is find out what QoS services they offer and what
you need to mark your traffic to so it will be treated properly within
their cloud. For instance, Verizon Business in the US offers only three
classes of services within their vBNS+ cloud - Gold, Silver, and Bronze.
Each of these "classes" of service correspond to a DSCP/ToS marking. To
take advantage of these classes of service, I need to mark my traffic
appropriately as it leaves my CE router towards their PE.
I hope this helps you out. Let me know if I misunderstood your
questions.
-Erik
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of ramarao
vadlamudi
Sent: Wednesday, December 30, 2009 1:35 PM
To: [email protected]
Subject: [OSL | CCIE_RS] QOS question
All,
Q1-
Can you please explain the default behaviour if you reserve 100% on the
interface bandwidth without using the "max-reserved bandwidth 100"
command? By default 25% of the bandwidth is allocated to the default
class. So how would my default class get served if I have no bandwidth
reserved for it.
Q2-
Also should you use the same class maps as your SP; when you use Layer 3
SP VPN for WAN carriage? For instance if I have 8 class maps and SP had
only 6 class maps, how would my traffic be treated in their SP network.
If 6 of my class-map maps to what SP has in their network and 2 of my
class-maps do not map to any thing in their network, will they treat my
class-maps which don't map to any of their class maps to their default
CM.
Thanks
Ramu
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