[c-nsp] cisco-nsp Digest, Vol 62, Issue 51 problem of both "ip route 0.0.0.0" and "ip

Sat Jan 12 14:07:44 EST 2008

Default routing  is recommended to used on stub networks. If you have configured ip routing on your switch and using a dynamic routing protocol you should be fine with a default gateway in case you need to access the switch and routing protocols are not working. Something else you could modify is the Swicth Database Modifier (SMD) to made a better used of the memory. After issuing the command you need to reload the switch.

SDM prefer ?
Access
Extended-match
routing
vlan

----- Original Message ----
From: "cisco-nsp-request at puck.nether.net" <cisco-nsp-request at puck.nether.net>
To: cisco-nsp at puck.nether.net
Sent: Saturday, January 12, 2008 11:42:02 AM
Subject: cisco-nsp Digest, Vol 62, Issue 51

Send cisco-nsp mailing list submissions to
    cisco-nsp at puck.nether.net

To subscribe or unsubscribe via the World Wide Web, visit
    https://puck.nether.net/mailman/listinfo/cisco-nsp
or, via email, send a message with subject or body 'help' to
    cisco-nsp-request at puck.nether.net

You can reach the person managing the list at
    cisco-nsp-owner at puck.nether.net

When replying, please edit your Subject line so it is more specific
than "Re: Contents of cisco-nsp digest..."

Today's Topics:

   1. Re: TCP Throughput / MTU problem ? with Cisco 7304 and MPLS
      VPN's (Mikael Abrahamsson)
   2. Re: tcpdump on ios? (Gert Doering)
   3. problem of both "ip route 0.0.0.0" and "ip default-gateway"
      configured (Sami Joseph)
   4. Re: problem of both "ip route 0.0.0.0" and "ip
      default-gateway" configured (sthaug at nethelp.no)
   5. Re: tcpdump on ios? (Luan Nguyen)
   6. Re: problem of both "ip route 0.0.0.0" and "ip
      default-gateway" configured (Jon Lewis)
   7. Re: MPLS hardware (Paul Stewart)
   8. Re: problem of both "ip route 0.0.0.0" and "ip
      default-gateway" configured (Paul Stewart)
   9. Re: problem of both "ip route 0.0.0.0" and "ip
      default-gateway" configured (Kim Onnel)

----------------------------------------------------------------------

Message: 1
Date: Sat, 12 Jan 2008 08:30:14 +0100 (CET)
From: Mikael Abrahamsson <swmike at swm.pp.se>
Subject: Re: [c-nsp] TCP Throughput / MTU problem ? with Cisco 7304
    and MPLS VPN's
To: cisco-nsp at puck.nether.net
Message-ID: <alpine.DEB.1.00.0801120829270.1149 at uplift.swm.pp.se>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

On Sat, 12 Jan 2008, Peter Rathlev wrote:

> But you still can't (shouldn't) use an interface MTU lower that the
 MPLS 
> MTU. Your interface MTU should be larger than the "X" MTU for any
 "X".

Why?

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se

------------------------------

Message: 2
Date: Sat, 12 Jan 2008 14:04:39 +0100
From: Gert Doering <gert at greenie.muc.de>
Subject: Re: [c-nsp] tcpdump on ios?
To: Kim Onnel <karim.adel at gmail.com>
Cc: Gert Doering <gert at greenie.muc.de>,    "cisco-nsp at puck.nether.net"
    <cisco-nsp at puck.nether.net>
Message-ID: <20080112130438.GM1867 at greenie.muc.de>
Content-Type: text/plain; charset="us-ascii"

Hi,

On Sat, Jan 12, 2008 at 03:21:09AM +0200, Kim Onnel wrote:
> if we are talking about hardware switching platforms then i believe
 it makes
> sense that it will only sniff process switched traffic, so why is it
 useless
> then?

If you have process switched traffic, something is wrong with your 
network setup.  Some features just plain do not work without CEF (like
"MPLS"), others are horribly slow or cause insane amount of CPU load.

> IMHO, it is very difficult to design a router that will capture
 traffic
> being hardware switched, am i correct?

SPAN/RSPAN/ERSPAN exit and work very well :-)

gert
-- 
USENET is *not* the non-clickable part of WWW!

 //www.muc.de/~gert/
Gert Doering - Munich, Germany                            
 gert at greenie.muc.de
fax: +49-89-35655025                      
  gert at net.informatik.tu-muenchen.de
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 304 bytes
Desc: not available
Url :
 https://puck.nether.net/pipermail/cisco-nsp/attachments/20080112/9cd02235/attachment-0001.bin 

------------------------------

Message: 3
Date: Sat, 12 Jan 2008 15:52:23 +0200
From: "Sami Joseph" <sami.joseph at gmail.com>
Subject: [c-nsp] problem of both "ip route 0.0.0.0" and "ip
    default-gateway"    configured
To: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
Message-ID:
    <9da37ec40801120552p232dcb50hfcd50b7e32756436 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Hello,

Someone mentioned that configuring both commands on the same
 router/switch
causes trouble, i wonder if someone can help me understand why?

1) ip route 0.0.0.0 next-hop
2) ip default-gateway next-hop

Also why would configuring a couple of static routes with the next hop
 being
an interface name not an ip address cause high CPU ?

Thanks,
Sam

------------------------------

Message: 4
Date: Sat, 12 Jan 2008 16:27:12 +0100 (CET)
From: sthaug at nethelp.no
Subject: Re: [c-nsp] problem of both "ip route 0.0.0.0" and "ip
    default-gateway" configured
To: sami.joseph at gmail.com
Cc: cisco-nsp at puck.nether.net
Message-ID: <20080112.162712.74695546.sthaug at nethelp.no>
Content-Type: Text/Plain; charset=us-ascii

> Someone mentioned that configuring both commands on the same
 router/switch
> causes trouble, i wonder if someone can help me understand why?
> 
> 1) ip route 0.0.0.0 next-hop
> 2) ip default-gateway next-hop

Why do you *want* to configure both? 1 is supposed to be used for an L3
box (router), 2 is supposed to be used for an L2 box (switch).

> Also why would configuring a couple of static routes with the next
 hop being
> an interface name not an ip address cause high CPU ?

If the interface in question is a broadcast medium (Ethernet), the
 router
doesn't know the next-hop address, resulting in a high rate of ARPs.
 This
has been dicussed on the list many times before, and the advice is
 simple:
Don't do it!

Steinar Haug, Nethelp consulting, sthaug at nethelp.no

------------------------------

Message: 5
Date: Sat, 12 Jan 2008 10:42:49 -0500
From: "Luan Nguyen" <luan.m.nguyen at gmail.com>
Subject: Re: [c-nsp] tcpdump on ios?
To: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
Message-ID:
    <19cdad00801120742k5e1c3b57q902d81004fda1716 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

But on a simple router, to track down a problem for a few seconds...
no logging console
logging buffer xxxx debugging
no ip route-cache on interfaces
access-list to match or set interface condition
debug ip packet detail <access-list> (dump).

would do fine?

-lmn

On Jan 12, 2008 8:04 AM, Gert Doering <gert at greenie.muc.de> wrote:

> Hi,
>
> On Sat, Jan 12, 2008 at 03:21:09AM +0200, Kim Onnel wrote:
> > if we are talking about hardware switching platforms then i believe
 it
> makes
> > sense that it will only sniff process switched traffic, so why is
 it
> useless
> > then?
>
> If you have process switched traffic, something is wrong with your
> network setup.  Some features just plain do not work without CEF
 (like
> "MPLS"), others are horribly slow or cause insane amount of CPU load.
>
> > IMHO, it is very difficult to design a router that will capture
 traffic
> > being hardware switched, am i correct?
>
> SPAN/RSPAN/ERSPAN exit and work very well :-)
>
> gert
> --
> USENET is *not* the non-clickable part of WWW!
>
> //www.muc.de/~gert/
> Gert Doering - Munich, Germany
> gert at greenie.muc.de
> fax: +49-89-35655025
> gert at net.informatik.tu-muenchen.de
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>

------------------------------

Message: 6
Date: Sat, 12 Jan 2008 11:25:01 -0500 (EST)
From: Jon Lewis <jlewis at lewis.org>
Subject: Re: [c-nsp] problem of both "ip route 0.0.0.0" and "ip
    default-gateway" configured
To: sthaug at nethelp.no
Cc: cisco-nsp at puck.nether.net
Message-ID: <Pine.LNX.4.61.0801121119160.3306 at soloth.lewis.org>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

On Sat, 12 Jan 2008 sthaug at nethelp.no wrote:

>> Someone mentioned that configuring both commands on the same
 router/switch
>> causes trouble, i wonder if someone can help me understand why?
>>
>> 1) ip route 0.0.0.0 next-hop
>> 2) ip default-gateway next-hop
>
> Why do you *want* to configure both? 1 is supposed to be used for an
 L3
> box (router), 2 is supposed to be used for an L2 box (switch).

AFAIK, ip default-gateway is only used when IP routing is
 off/unsupported. 
It can be useful if a device ends up booting into boot IOS that doesn't

support routing (like some of the older run from flash platforms during
 a 
software upgrade where you have to reboot from ROM, download new code
 to 
flash, and then boot the new code).  I've got lots of gear with both a 
default route and an ip default-gateway and no problems.

> If the interface in question is a broadcast medium (Ethernet), the
 router
> doesn't know the next-hop address, resulting in a high rate of ARPs.
 This
> has been dicussed on the list many times before, and the advice is
 simple:
> Don't do it!

It can work...but its very delicate and really pisses people off when 
someone with more clue is asked to take over management of the network.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________

------------------------------

Message: 7
Date: Sat, 12 Jan 2008 11:34:40 -0500
From: "Paul Stewart" <paul at paulstewart.org>
Subject: Re: [c-nsp] MPLS hardware
To: "'Jon Lewis'" <jlewis at lewis.org>
Cc: cisco-nsp at puck.nether.net
Message-ID: <007901c85539$09b1e750$1d15b5f0$@org>
Content-Type: text/plain;    charset="us-ascii"

Thanks Jon (and everyone) .. the information flowing in from the list
 has
been AWESOME...;)

I'm playing with the idea that maybe we implement a few
 7206VXR/NPE-G2's
into our core/distribution and feed our 6500's from them ... we are a
 low
traffic network (300-400Mbps routed/switched across the entire
infrastructure) ... but then I wonder about that kind of traffic on a
7206VXR and take a complete 360 degree thought pattern....

What I'm trying to figure out is how I can come up with two P routers
 (for
redundancy, not capacity) and a few PE routers.  Having said that we
 have a
GSR that isn't doing a lot of stuff right at the moment (Cisco 12012,
 dual
PRP-2, engine 0 cards though), rest is 7206VXR and 6509 (sup2) based...
 if I
could find a way to "wrap" our existing network - today the 6500's work
perfectly for their purpose so I can find a way to leave them but bring
 MPLS
in "around" them that would be perfect....

Budget is a HUGE issue which doesn't normally play well with the word
 MPLS
involved...;)

Paul

-----Original Message-----
From: Jon Lewis [mailto:jlewis at lewis.org] 
Sent: Friday, January 11, 2008 10:27 PM
To: Paul Stewart
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] MPLS hardware

On Thu, 10 Jan 2008, Paul Stewart wrote:

> If we leave the whole VPSL component out and want to do "MPLS" - is
 there
> any documents on Cisco.com that outline what the Sup2 platform is
 capable
of
> when it comes to MPLS in general?  Somewhere I would think that Sup2
 can
do
> *some* MPLS stuff or am I just simply wrong? ;)

On regular interfaces/line cards, it won't even tag-switch (i.e. be a P

router).  If you want MPLS in the 6500, you need a Sup32 or Sup720 (3B
 or 
3BXL)...and if you think full BGP routes is something you might want,
 then 
the Sup720-3bxl is your only option in the 6500.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________

-- 
No virus found in this incoming message.
Checked by AVG Free Edition. 
Version: 7.5.516 / Virus Database: 269.19.1/1219 - Release Date:
 1/11/2008
10:19 AM

------------------------------

Message: 8
Date: Sat, 12 Jan 2008 11:36:24 -0500
From: "Paul Stewart" <paul at paulstewart.org>
Subject: Re: [c-nsp] problem of both "ip route 0.0.0.0" and "ip
    default-gateway" configured
To: "'Jon Lewis'" <jlewis at lewis.org>, <sthaug at nethelp.no>
Cc: cisco-nsp at puck.nether.net
Message-ID: <007a01c85539$487e9050$d97bb0f0$@org>
Content-Type: text/plain;    charset="us-ascii"

We've ran across both before when a layer3 switch is involved that was
previously used for layer2 functions only - worked fine, but we did go
 back
and remove the "ip default-gateway" statement...

Paul

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Jon Lewis
Sent: Saturday, January 12, 2008 11:25 AM
To: sthaug at nethelp.no
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] problem of both "ip route 0.0.0.0" and "ip
default-gateway" configured

On Sat, 12 Jan 2008 sthaug at nethelp.no wrote:

>> Someone mentioned that configuring both commands on the same
router/switch
>> causes trouble, i wonder if someone can help me understand why?
>>
>> 1) ip route 0.0.0.0 next-hop
>> 2) ip default-gateway next-hop
>
> Why do you *want* to configure both? 1 is supposed to be used for an
 L3
> box (router), 2 is supposed to be used for an L2 box (switch).

AFAIK, ip default-gateway is only used when IP routing is
 off/unsupported. 
It can be useful if a device ends up booting into boot IOS that doesn't

support routing (like some of the older run from flash platforms during
 a 
software upgrade where you have to reboot from ROM, download new code
 to 
flash, and then boot the new code).  I've got lots of gear with both a 
default route and an ip default-gateway and no problems.

> If the interface in question is a broadcast medium (Ethernet), the
 router
> doesn't know the next-hop address, resulting in a high rate of ARPs.
 This
> has been dicussed on the list many times before, and the advice is
 simple:
> Don't do it!

It can work...but its very delicate and really pisses people off when 
someone with more clue is asked to take over management of the network.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
_______________________________________________
cisco-nsp mailing list  cisco-nsp at puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/

-- 
No virus found in this incoming message.
Checked by AVG Free Edition. 
Version: 7.5.516 / Virus Database: 269.19.1/1220 - Release Date:
 1/11/2008
6:09 PM

------------------------------

Message: 9
Date: Sat, 12 Jan 2008 18:42:00 +0200
From: "Kim Onnel" <karim.adel at gmail.com>
Subject: Re: [c-nsp] problem of both "ip route 0.0.0.0" and "ip
    default-gateway" configured
To: "Jon Lewis" <jlewis at lewis.org>
Cc: cisco-nsp at puck.nether.net, sthaug at nethelp.no
Message-ID:
    <e05f39290801120842l345c7032k6e572ae5a464816 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

so if both are configured on a 3750 for example, there is no harm done?

On Jan 12, 2008 6:25 PM, Jon Lewis <jlewis at lewis.org> wrote:

> On Sat, 12 Jan 2008 sthaug at nethelp.no wrote:
>
> >> Someone mentioned that configuring both commands on the same
> router/switch
> >> causes trouble, i wonder if someone can help me understand why?
> >>
> >> 1) ip route 0.0.0.0 next-hop
> >> 2) ip default-gateway next-hop
> >
> > Why do you *want* to configure both? 1 is supposed to be used for
 an L3
> > box (router), 2 is supposed to be used for an L2 box (switch).
>
> AFAIK, ip default-gateway is only used when IP routing is
 off/unsupported.
> It can be useful if a device ends up booting into boot IOS that
 doesn't
> support routing (like some of the older run from flash platforms
 during a
> software upgrade where you have to reboot from ROM, download new code
 to
> flash, and then boot the new code).  I've got lots of gear with both
 a
> default route and an ip default-gateway and no problems.
>
> > If the interface in question is a broadcast medium (Ethernet), the
> router
> > doesn't know the next-hop address, resulting in a high rate of
 ARPs.
> This
> > has been dicussed on the list many times before, and the advice is
> simple:
> > Don't do it!
>
> It can work...but its very delicate and really pisses people off when
> someone with more clue is asked to take over management of the
 network.
>
>
 ----------------------------------------------------------------------
>  Jon Lewis                   |  I route
>  Senior Network Engineer     |  therefore you are
>  Atlantic Net                |
> _________
 http://www.lewis.org/~jlewis/pgp<http://www.lewis.org/%7Ejlewis/pgp>for PGP public key_________
>

------------------------------

_______________________________________________
cisco-nsp mailing list
cisco-nsp at puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-nsp

End of cisco-nsp Digest, Vol 62, Issue 51
*****************************************

      ____________________________________________________________________________________
Never miss a thing.  Make Yahoo your home page. 
http://www.yahoo.com/r/hs