Re: Re :Re: Re :Re: Re :Re: Static Route

From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Sun Apr 01 2007 - 23:17:02 ART


Think about the "issue" for a second. If a router learns a summarized route
(i.e. /23) that overlaps a more specific route (i.e. /24) how will it create
a "loop"?

Remember that the router will use the more specific route over the
summarized route. Now if there is not a more specific route traffic for the
"overlapped" route (i.e. /24) will be forwarded toward the summary route
(i.e. /23).

-- 

Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP) bdennis@internetworkexpert.com Internetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Direct: 775-745-6404 (Outside the US and Canada)

On 4/1/07 6:41 PM, "daniel" <danyccie@rediffmail.com> wrote:

> Thank you for your reply. I find an issue with this > summerisation.10.10.103.0/24 - 10.10.13.110.10.104.0/23 - 10.10.13.1These two > covers 103,104 and 105 > 10.10.100.0/22 - 10.10.13.2 10.10.106.0/24 - 10.10.13.2These two covers > 100,101,102,103 and 106There is an overlap of 103 which will create a loop in > my scinario and goof up things.So can you give me a little more accurate > solution.Thanks,Dany.On Mon, 2 Apr 2007 06:15:42 +1000 \"CCIE 19999\" wrote > Dany, I think, if you do the following summarization, you should be able to > squeeze the 6 routes into 4. 10.10.103.0/24 10.10.104.0/24 &amp; > 10.10.105.0/24 all going out through 10.10.13.1 When converting the third > octet into binary we get the following: 0110 0111 - 103 0110 1000 - 104 0110 > 1001 - 105 Consider only last two and the difference is only in the last bit, > and we can summarize these 3 routes into two as: 10.10.103.0/24 - 10.10.13.1 > and the summarised 2nd and third as: 10.10.104.0/23 - 10.10.13.1 By applying > the same technique you can summarise the 10.10.101.0/24 &amp; 10.10.102.0/24 > into 10.10.100.0/22 - 10.10.13.2 and 10.10.106.0/24 - 10.10.13.2 Hope this > helps. RS ----! > - Original Message ----- From: \"daniel \" To: Cc: Sent: Monday, April 02, > 2007 3:34 AM Subject: Re :Re: Re :Re: Static Route &gt; OK. I understand.No > let me change the scinario a little bit.How can I &gt; squeeze the following > static routes in to 4. &gt; router#(config) ip route 10.10.103.0 255.255.255.0 > &gt; 10.10.13.1router#(config) ip route 10.10.104.0 255.255.255.0 &gt; > 10.10.13.1router#(config) ip route 10.10.105.0 255.255.255.0 10.10.13.1 &gt; > &gt; router#(config) ip route 10.10.101.0 255.255.255.0 &gt; > 10.10.12.1router#(config) ip route 10.10.102.0 255.255.255.0 &gt; > 10.10.12.1router#(config) ip route 10.10.106.0 255.255.255.0 &gt; > 10.10.12.1Regards,Dany.On Mon, 2 Apr 2007 00:30:55 +1000 \"Radioactive &gt; > Frog\" wrote XOR the 3rd ocatate and put tha tin the ACL Similar to below &gt; > and I believe that you can squeeze your routes/ACL\'s in 3 lines. 128 64 &gt; > 32 16 8 4 2 1 103= 01100111 104= 01101000 105= &gt; 01101001 > ------------------------ = 0000111 = 4+2+1 = &! > gt; 5 ----------------------- 10.10.103.0 255.255.5.0 &gt; &gt! > ; Hi, &g > > t; &gt; &gt; Thank you for your reply. My problem is I\'m allowed to use only > 4 &gt; &gt; access-lists to acheive the same. Please tell me how to do this. > &gt; &gt; Thanks, &gt; &gt; Dany. &gt; &gt; &gt; &gt; On Sun, 1 Apr 2007 > 19:28:13 &gt; +1000 \"Radioactive Frog\" wrote Hi Daniel, It\'s &gt; preety > much very &gt; simple. Assuming you\'ve cisco router. Otherwise every &gt; > router have &gt; their different interface to configure. 1) Go to config t > &gt; ro! &gt; uter#config t router#(config) ip route 10.10.103.0 255.255.255.0 > &gt; &gt; 10.10.13.1 router#(config) ip route 10.10.104.0 255.255.255.0 &gt; > 10.10.13.1router#(config) ip route &gt; 10.10.105.0 255.255.255.0 &gt; > 10.10.13.1 2) router#config t router#(config) ip &gt; route 200.200.101.0 &gt; > 255.255.255.0 10.10.12.1 router#(config) ip route &gt; 200.200.102.0 &gt; > 255.255.255.0 10.10.12.1 router#(config) ip route &gt; 200.200.106.0 &gt; > 255.255.255.0 10.10.12.1 HTH, Frog &gt; &gt; Regards, &gt; Dany &gt; > ____________! > ___________________________________________________________ &gt; Subscription > information may be found at: &gt; http://www.groupstudy.com/list/CCIELab.html > &gt; &gt; Regards, &gt; Dany &gt; &gt; > _______________________________________________________________________ &gt; > Subscription information may be found at: &gt; > http://www.groupstudy.com/list/CCIELab.html > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html > > Regards, > Dany > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html



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