05-21-2007 06:58 AM - edited 03-03-2019 05:04 PM
have a question concerning how Cisco?s rate-limit command works.
Please allow me to explain by giving you an example.
Let?s say that I have a symmetrical dedicated 10 Mbps connection to the Internet at a business park.
Let?s also assume that I have 10 businesses in the business park who each want the same type of oversubscribed CIR Internet access.
The SLA for each business says that each business will get at least 1 Mbps upstream and 1 Mbps downstream whenever they need it.
We want each business to also be able to burst up to 5 Mbps when possible.
Of course, all 10 businesses cannot burst at 5 Mbps at the same time because that would exceed the 10 Mbps capacity of the pipe.
That is, each business gets at least its 1 Mbps guaranteed share of the 10 Mbps pipe when it needs it.
But any business will ?lend? any unused portion of its 1 Mbps guaranteed share of the pipe to the other businesses when the full share is not needed.
Of course, any ?borrowed? capacity should be instantaneously given back to its owner whenever the owner needs it.
And no one business should get more than 5 Mbps no matter how much unused capacity is available.
Can I use the rate-limit command to implement this type of sharing? If so, how?
Or does Cisco?s software only set fixed minimum and maximum information rates to create pipes whose capacities cannot be automatically and dynamically shared with other pipes going through the same router?
thank you
05-21-2007 09:14 AM
It is not rate-limiting that you should be looking at, its called CBWFQ. Where you shape the traffic.
For your example this could be the configuration
!
! Your access-list defining your internal ! traffic
access-list 101 permit ip x.x.x.x y.y.y.y any
access-list 102 permit ip a.a.a.a b.b.b.b any
.
.
.
access-list 110 permit ip c.c.c.c d.d.d.d any
!class maps matching your access-list
!
class-map 1cust
match address 101
!
class-map 2cust
match address 102
!
.
.
.
class-map 10cust
match address 110
!
policy-map shape-cbwfq
class 1cust
!gurantee of 1mbps shaping it to 5Mbps if !bandwidth available
bandwidth 1000
shape peak 5000000
class 2cust
bandwidth 1000
shape peak 5000000
.
.
.
class 10cust
bandwidth 1000
shape peak 5000000
!
interface fastethernet0/0
desc outside interface connected to internet
service out shape-cbwfq
!
HTH
-Hoogen
Do rate if this post is helpful :)
05-21-2007 09:22 AM
thank you .
Is this supported on the low end cisco routers , example, 1800 or 2800 routers with fast ethernet interface
05-21-2007 09:33 AM
ISR routers are new breed of routers. It does support this.
-Hoogen
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