[nsp] Not using "redist sta sub" in OSPF
Steve Francis
sfrancis@expertcity.com
Fri, 09 Aug 2002 11:59:27 -0700
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Matt Ryan wrote:
>I don't see the logic of using "network" statements over redistributing
>statics.
>
Assuming its a customer CPE, not administered by you, and there are no
alternate paths to it (conditions that were not specified in the
original post, but may well be true), then using statics and
redistributing via route map is appropriate.
In general, redistribution is bad. In OSPF, by default, a redistributed
route will be injected into OSPF as a type II external route. This
means it will flow to all areas, regardless of route summarization on
the ABR's, and could destroy the scalability of the network design. (Not
really an issue in a small simple net, unless you end up growing beyond
your plans.)
If the equipment is administered by you, I'd probably run OSPF on it.
If not, and there are alternate paths, you need BGP.
> If I have a customer connected on a leased line (numbered with a
>/30 or /31 subnet) and they have a /24 on the back of their CPE router how
>am I supposed to announce the route back into my IGP? Speak a routing
>protocol with the CPE device (which I'd say is much more dangerous than
>using statics)? Using a route-map as Ryan suggests would seem the pragmatic
>solution to avoid any screw-ups by adding an incorrect static.
>
>
>Matt.
>
>-----Original Message-----
>From: Ryan O'Connell [mailto:ryan@complicity.co.uk]
>Sent: 09 August 2002 10:49
>To: Mark Drayton; cisco-nsp@puck.nether.net
>Subject: Re: [nsp] Not using "redist sta sub" in OSPF
>
>
>On Fri, 9 Aug 2002 10:30:47 +0100 Mark Drayton
><mark.drayton@izrsolutions.com> wrote:
>
>>I have a few static routes pointing at frame relay subifs that I'd like
>>to get into OSPF, without using "redist sta sub" as that redistributes
>>all the static routes I have.
>>
>[snip]
>
>>I tried using "network 192.168.20.0 0.0.0.255 area 0" but that doesn't
>>work (not a surprise after consulting documentation). Is there a better
>>way to do this?
>>
>
>Use a route-map on the redistribute command, like this:
>
>router ospf 100
> redistribute static 1 subnets route-map static-to-ospf
>
>route-map static-to-ospf permit 10
> match ip address 1
>
>access-list 1 permit host 192.168.20.0
>
>--
> Ryan O'Connell - CCIE #8174
><ryan@complicity.co.uk> - http://www.complicity.co.uk
>
>I'm not losing my mind, no I'm not changing my lines,
>I'm just learning new things with the passage of time
>
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Matt Ryan wrote:<br>
<blockquote type="cite" cite="mid:B55BD6063157D411AA930008C707C7B101D3E601@BR-YK-XCHG-1">
<pre wrap="">I don't see the logic of using "network" statements over redistributing<br>statics.</pre>
</blockquote>
Assuming its a customer CPE, not administered by you, and there are no alternate
paths to it (conditions that were not specified in the original post, but
may well be true), then using statics and redistributing via route map is
appropriate.<br>
<br>
In general, redistribution is bad. In OSPF, by default, a redistributed route
will be injected into OSPF as a type II external route. This means it will
flow to all areas, regardless of route summarization on the ABR's, and could
destroy the scalability of the network design. (Not really an issue in a
small simple net, unless you end up growing beyond your plans.)<br>
<br>
If the equipment is administered by you, I'd probably run OSPF on it. If
not, and there are alternate paths, you need BGP.<br>
<blockquote type="cite" cite="mid:B55BD6063157D411AA930008C707C7B101D3E601@BR-YK-XCHG-1">
<pre wrap=""> If I have a customer connected on a leased line (numbered with a<br>/30 or /31 subnet) and they have a /24 on the back of their CPE router how<br>am I supposed to announce the route back into my IGP? Speak a routing<br>protocol with the CPE device (which I'd say is much more dangerous than<br>using statics)? Using a route-map as Ryan suggests would seem the pragmatic<br>solution to avoid any screw-ups by adding an incorrect static.<br><br><br>Matt.<br><br>-----Original Message-----<br>From: Ryan O'Connell [<a class="moz-txt-link-freetext" href="mailto:ryan@complicity.co.uk">mailto:ryan@complicity.co.uk</a>]<br>Sent: 09 August 2002 10:49<br>To: Mark Drayton; <a class="moz-txt-link-abbreviated" href="mailto:cisco-nsp@puck.nether.net">cisco-nsp@puck.nether.net</a><br>Subject: Re: [nsp] Not using "redist sta sub" in OSPF<br><br><br>On Fri, 9 Aug 2002 10:30:47 +0100 Mark Drayton<br><a class="moz-txt-link-rfc2396E" href="mailto:mark.drayton@izrsolutions.com"><
mark.drayton@izrsolutions.com></a> wrote:<br></pre>
<blockquote type="cite">
<pre wrap="">I have a few static routes pointing at frame relay subifs that I'd like<br>to get into OSPF, without using "redist sta sub" as that redistributes<br>all the static routes I have.<br></pre>
</blockquote>
<pre wrap=""><!---->[snip]<br></pre>
<blockquote type="cite">
<pre wrap="">I tried using "network 192.168.20.0 0.0.0.255 area 0" but that doesn't<br>work (not a surprise after consulting documentation). Is there a better<br>way to do this?<br></pre>
</blockquote>
<pre wrap=""><!----><br>Use a route-map on the redistribute command, like this:<br><br>router ospf 100<br> redistribute static 1 subnets route-map static-to-ospf<br><br>route-map static-to-ospf permit 10<br> match ip address 1<br><br>access-list 1 permit host 192.168.20.0<br><br>--<br> Ryan O'Connell - CCIE #8174<br><a class="moz-txt-link-rfc2396E" href="mailto:ryan@complicity.co.uk"><ryan@complicity.co.uk></a> - <a class="moz-txt-link-freetext" href="http://www.complicity.co.uk">http://www.complicity.co.uk</a><br><br>I'm not losing my mind, no I'm not changing my lines,<br>I'm just learning new things with the passage of time<br><br>_______________________________________________<br>cisco-nsp mailing list <a class="moz-txt-link-abbreviated" href="mailto:real_name)s@puck.nether.net">real_name)s@puck.nether.net</a><br><a class="moz-txt-link-freetext" href="http://puck.nether.net/mailman/listinfo/cisco-nsp">http://puck.nether.net/mailman/listinfo/cisco
-nsp</a><br>archive at <a class="moz-txt-link-freetext" href="http://puck.nether.net/pipermail/cisco-nsp/">http://puck.nether.net/pipermail/cisco-nsp/</a><br><br>------------------------------------------------------------------------------<br>Live Life in Broadband<br><a class="moz-txt-link-abbreviated" href="http://www.telewest.co.uk">www.telewest.co.uk</a><br><br><br>The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material.<br>Statements and opinions expressed in this e-mail may not represent those of the company. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender immediately and delete the material from any computer.<br><br><br>============================================================
==================<br><br>_______________________________________________<br>cisco-nsp mailing list <a class="moz-txt-link-abbreviated" href="mailto:real_name)s@puck.nether.net">real_name)s@puck.nether.net</a><br><a class="moz-txt-link-freetext" href="http://puck.nether.net/mailman/listinfo/cisco-nsp">http://puck.nether.net/mailman/listinfo/cisco-nsp</a><br>archive at <a class="moz-txt-link-freetext" href="http://puck.nether.net/pipermail/cisco-nsp/">http://puck.nether.net/pipermail/cisco-nsp/</a><br></pre>
</blockquote>
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