Rick Ernst wrote:
The stars are starting to come into alignment and I'm about ready to
order equipment for a network refresh.
I currently have a edge/core/aggregation model with 7206VXR/NPE-G1 at the
edge, 7500/RSP16/GEIP+ in the core, and various aggregation devices from
5500/RSM to 7500/RSP8 and dialup, DSL, etc. We are migrating from OC-3 to
GigE at our edge.
We currently push about 300mbs in each direction and that is expected to
grow by at least 100mbs this year. The rate of growth has increased
dramatically.
I'm planning on collapsing the border/core into a pair of
7600/Sup720-3BXLs, and it looks like they will be almost idle with this
amount of load.
The problem I am running into is spec'ing the aggregation layer. Almost
all of our traffic is ethernet now, and all the interfaces need
bi-drectional rate-limiting/traffic-shaping/policing. We have a variable
bandwidth model and need to cap traffic at 1Mbs granularity. 1,5, and
10Mbs connections are common, and 20,50,100Mbs connections exist with a
200Mbs pipe in process.
The only traffic management I have used in the past is Cisco's rate-limit,
and it is very CPU intensive. I'm trying to find out if a Sup720/RSP720
can handle hundreds of interfaces, each being rate-limited in some manner.
The Cisco data sheet is vague about "some features" and "QoS" in
hardware, but isn't specific about what features are in hardware.
Is the Sup720 (RSP720 a better answer?) sufficient? Is traffic-management
in hardware, and should I be looking at rate-limit or some different
mechanism?
QoS on the 6500/7600 platform is a pretty involved topic. You will want
to read up on it carefully. See:
http://www.cisco.com/en/US/docs/routers/7600/ios/12.2SR/configuration/guide/qos.html
Assuming you're talking about "LAN" lincards e.g. 67xx series, then:
* qos is done in hardware
* the capabilities are reasonable, but limited and a bit complex
because it's done in hardware
* the capabilities depend on the exact model of linecard - some have
fewer queues, smaller buffers, only 6708 support ingress DSCP mapping to
queues etc.
In particular, you want to watch ingress rate limiting very carefully.
My (limited) understanding is that it'll be tricky to do what you want.
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