RE: traffic delay insertion

From: Alex Ouraev (ualexv@gmail.com)
Date: Wed Jan 24 2007 - 14:00:41 ART

You can control it by introducing more vrfs into the "chain" thus increasing
and decreasing delay to get close to targeted parameter. With all other
variables equal in an isolated test environment you get fairly controllable
result

 

HTH

 

Alex

 

  _____

From: petrsoft@gmail.com [mailto:petrsoft@gmail.com] On Behalf Of Petr
Lapukhov
Sent: Wednesday, January 24, 2007 10:22 AM
To: Alex Ouraev
Cc: ccielab@groupstudy.com
Subject: Re: traffic delay insertion

 

I would still recommend to use FreeBSD/Linux based tools, like dummynet, as
it
was previously mentioned.

While funny, the "repetitive VRFs" scheme has serious problem: you could not

predictively control the introduced delay/loss parameters. Worst of it,
delay
could vary with router/interface load in non-linear manner.

After all it makes little sense to utilize poorly-controlled device for
modeling
in lab environment, since the resulting data will have low statistical
value.

You may also opt to look at software modeling tools like NS2, though they
have more scientific, rather than practical application :)

HTH 

-- 
Petr Lapukhov, CCIE #16379 (R&S/Security)
petr@internetworkexpert.com

Internetwork Expert, Inc.
http://www.InternetworkExpert.com

2007/1/24, Alex Ouraev <ualexv@gmail.com>:

I have used the following method to get close to production LD delay:

ip vrf 1
  rd 0:1

ip vrf 2
  rd 0:2

int tun 1
  ip vrf forwarding 1
  ip add 10.0.0.1 255.255.255.0
  tunnel source 5.0.0.1
  tunnel destination 5.0.0.2
  ip mtu 1500

int tun 2
  ip vrf forwarding 2
  ip add 10.0.0.2 255.255.255.0
  tunnel source 5.0.0.2
  tunnel destination 5.0.0.1
  ip mtu 1500

int loop 0
  ip add 5.0.0.1 255.255.255.0
  ip add 5.0.0.2 255.255.255.0 secondary

Note:

  1. int loop 0 ins not included into any vrf 
  2. default ip mtu for a tunnel = 1490. ip mtu 1500 fixes that

Routing within:

router eigrp 100
  address-famuly ipv4 vrf 1
  network 10.0.0.0
  no auto-summary
  autonomous-system 100

  address-famuly ipv4 vrf 2
  network 10.0.0.0
  no auto-summary
  autonomous-system 100

etc.

Debug:

sh ip route vrf 1|2
ping vrf 1|2 
sh ip eigrp vrf 1|2 neigh
etc...

HTH

Alex

-----Original Message-----
From: nobody@groupstudy.com [mailto: nobody@groupstudy.com
<mailto:nobody@groupstudy.com> ] On Behalf Of Pat
Sent: Tuesday, January 23, 2007 11:26 PM
To: Group Study
Subject: traffic delay insertion

Hi GS,
I don't believe this function exists at all, but just to double-check, 
in case I missed something simple.

Background: Delay insertion was desired in a lab environment to
simulate production network delay form City A to City B.

Thanks!
Pat
#16228

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