RE: OSPF virtual link Question [7:3154]
A virtual link allows an ABR to Hop accross a transit area to reach area 0. Generally speaking, they are to be avoided. Virtual links are more acceptable in a migration situation, or if Area 0 has been segmented (I.e. as a temp fix). The little book of common sense says if it isn't broke then there is no reason to fix it, unless you are a consultant and the customer is willing to pay for it. Ejay Hire -Original Message- From: Vincent Chong [mailto:[EMAIL PROTECTED]] Sent: Friday, May 04, 2001 3:54 AM To: [EMAIL PROTECTED] Subject: OSPF virtual link Question [7:3154] Hi; The following scenario [RouteA area0][area0 RouterB area1]<--[area1 RouterC area4] | | | | |__Virtual link___| Does this topology is valid in OSPF? I belive that the configuration has topology error, but the owener said it was working fine without authenication. For I am not familiar with Virtual link, ay comment are welcome? Best Rgds; Vincent Chong FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3206&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF virtual link Question [7:3154]
Hi; Thank you. Vincent Chong Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3173&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF virtual link Question [7:3154]
Vincent- this is a textbook scenario for virtual links to Area 0. You must realize that you will be building a 1 way LSA tunnel (configured on both sides). How you look @ this, is that Router C is broke. It can't inform Area 4 because it's not an ABR. You need to make the connection "from & through" Area 1 to Area 0's, pointed @ the OSPF router ID of Router B (vise versa with the other side's config). Keep in mind that you are traversing Area 1 & Area 4 does not need configuring. The commands are pretty simple & again must be carried out on both sides (Routers B & C). When you have built the Virtual Link, Router C will have "theoretically" Area 0 under the hood. This is what allows Area 4 to work, it will be touching Area 0 now. You will notice when you are done, Router C now looks @ Area 0 as "O" & not "IA." As far as your authentication question... this has nothing to do with your problem. Authentication locks down Area by Area, so that routes/ LSA's are only permitted to Athenticat-able OSPF routers or routers in other Areas that obtain updates outside the Authenticated Area. In short, Authentication stops someone from plugging in a router within your Authenticated Area & picking up LSA info. All the best !!! Phil - Original Message - From: Vincent Chong To: Sent: Friday, May 04, 2001 3:53 AM Subject: OSPF virtual link Question [7:3154] > Hi; > > The following scenario > > > [RouteA area0][area0 RouterB area1] RouterC area4] > | > | > | > | > |__Virtual link___| > > Does this topology is valid in OSPF? > > I belive that the configuration has topology error, but the owener > said it was > working fine without authenication. > > For I am not familiar with Virtual link, ay comment are welcome? > > Best Rgds; > Vincent Chong > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3172&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF virtual link Question [7:3154]
I don't know what you mean by OSPF area rule, nor by the virtual link rule, but: In order to route from one of "not-backbone OSPF area" to another "not-backbone OSPF area", you need to cross the backbone area (area 0). For this reason, if one has two chained areas that do not "share" the backbone area, one has to use virtual links. Virtual links have following requirements: It must be established between two routers that share the same area (in this case, router B and router C). One of these two routers must be connected directly to the backbone (in this case, router B). However, if, in your network, you only have these areas, it would be worth to make area 1 as the backbone (area 0). -- Charles Lehmann ""Vincent Chong"" a icrit dans le message news: [EMAIL PROTECTED] > Hi; > > Due to the mail system incompatiable, the message was truncated, > I will provide more information to let you guys have more information. > > Area 0 is formed by Router A and Router B > > Area 1 is formed by Router B and Router C > > Area 4 is formed by Router C only. > > Router C set up a virtual link with Router A. > > The pesron who set up the topology said that it was a valid topoloy without > authenication > > But I am not agree, because the topology violate the OSPF area rule, virtual > link rule, this toplogy > will not function as expected no matter authenication or not. > > For I am not a OSPF expert, I would like to hear any advice, suggestion, > discussion. > > Any comment will be welcome. > > TIA > Vincent Chong > > ""Vincent Chong"" Hi; > > > > The following scenario > > > > > > [RouteA area0][area0 RouterB area1] RouterC area4] > > | > > | > > | > > | > > |__Virtual link___| > > > > Does this topology is valid in OSPF? > > > > I belive that the configuration has topology error, but the owener > > said it was > > working fine without authenication. > > > > For I am not familiar with Virtual link, ay comment are welcome? > > > > Best Rgds; > > Vincent Chong > > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3168&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF virtual link Question [7:3154]
Hi; Due to the mail system incompatiable, the message was truncated, I will provide more information to let you guys have more information. Area 0 is formed by Router A and Router B Area 1 is formed by Router B and Router C Area 4 is formed by Router C only. Router C set up a virtual link with Router A. The pesron who set up the topology said that it was a valid topoloy without authenication But I am not agree, because the topology violate the OSPF area rule, virtual link rule, this toplogy will not function as expected no matter authenication or not. For I am not a OSPF expert, I would like to hear any advice, suggestion, discussion. Any comment will be welcome. TIA Vincent Chong ""Vincent Chong"" Hi; > > The following scenario > > > [RouteA area0][area0 RouterB area1] RouterC area4] > | > | > | > | > |__Virtual link___| > > Does this topology is valid in OSPF? > > I belive that the configuration has topology error, but the owener > said it was > working fine without authenication. > > For I am not familiar with Virtual link, ay comment are welcome? > > Best Rgds; > Vincent Chong > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3159&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF virtual link Question [7:3154]
Configuration topology is okay. In this case you have area 1 as a transit area. It should work fine without any authentication. The thing to know, however, is that the configuration command is a bit misleading: (config-router)#area n virtual-link partner-router-id Where n is, in this case 1. The router ids should be set as being the IP address coded on the first loopback interface. By doing so, you prevent OSPF to pick up the "highest" IP address among all addresses coded on the physical interfaces. Coding a loopback interface with an IP address forces OSPF to use that address as the router ID (so you can control it... and you prevent having bad surprises if you change IP addresses on the physical interfaces). Of course the similar statement has to be coded on the partner router... The misleading thing here is that you code the area as being a virtual-link... The full syntax can be found at: http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr rp_r/1rfospf.htm#xtocid64137 Kind regards -- Charles Lehmann, CCNA, CCDA ""Vincent Chong"" a icrit dans le message news: [EMAIL PROTECTED] > Hi; > > The following scenario > > > [RouteA area0][area0 RouterB area1] RouterC area4] > | > | > | > | > |__Virtual link___| > > Does this topology is valid in OSPF? > > I belive that the configuration has topology error, but the owener > said it was > working fine without authenication. > > For I am not familiar with Virtual link, ay comment are welcome? > > Best Rgds; > Vincent Chong > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3156&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF virtual link Question [7:3154]
Hi; The following scenario [RouteA area0][area0 RouterB area1]<--[area1 RouterC area4] | | | | |__Virtual link___| Does this topology is valid in OSPF? I belive that the configuration has topology error, but the owener said it was working fine without authenication. For I am not familiar with Virtual link, ay comment are welcome? Best Rgds; Vincent Chong Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=3154&t=3154 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF virtual link question
WHERE IS THE DIAGRAM -Original Message- From: Manish Patel [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 26, 2000 5:58 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: OSPF virtual link question Consider the above OSPF network. You have configured a virtual path to connect Area 3 with Area 0. What is your assessment of this network? 1. The network will work. However, you must configure a second virtual link through router B to ensure there are no routing loops. 2. The network will not work. Area 3 must be directly connected to Area 0. 3.The network will work properly with no redundant hops. 4.network will work. However, it contains sub-optimal routing as packets from router D to router C must transit router A 5.network will not work. A routing loop exists as packets destined for router C from router D must pass through router C twice. Thanks in advance. Regards MK _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF virtual link question
The network diagram isn't attached, but... It's 4, in my opinion... (from brainbench, right? :) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Manish Patel Sent: Tuesday, December 26, 2000 5:58 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: OSPF virtual link question Consider the above OSPF network. You have configured a virtual path to connect Area 3 with Area 0. What is your assessment of this network? 1. The network will work. However, you must configure a second virtual link through router B to ensure there are no routing loops. 2. The network will not work. Area 3 must be directly connected to Area 0. 3.The network will work properly with no redundant hops. 4.network will work. However, it contains sub-optimal routing as packets from router D to router C must transit router A 5.network will not work. A routing loop exists as packets destined for router C from router D must pass through router C twice. Thanks in advance. Regards MK _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF virtual link question
ummm i think something is missing ? Which above OSP network ? -Original Message- From: Manish Patel [mailto:[EMAIL PROTECTED]] Sent: Wednesday, December 27, 2000 9:58 AM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: OSPF virtual link question Consider the above OSPF network. You have configured a virtual path to connect Area 3 with Area 0. What is your assessment of this network? 1. The network will work. However, you must configure a second virtual link through router B to ensure there are no routing loops. 2. The network will not work. Area 3 must be directly connected to Area 0. 3.The network will work properly with no redundant hops. 4.network will work. However, it contains sub-optimal routing as packets from router D to router C must transit router A 5.network will not work. A routing loop exists as packets destined for router C from router D must pass through router C twice. Thanks in advance. Regards MK _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF virtual link question
Well, it would help immensely if there were a diagram involved. :-> -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Manish Patel Sent: Tuesday, December 26, 2000 2:58 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: OSPF virtual link question Consider the above OSPF network. You have configured a virtual path to connect Area 3 with Area 0. What is your assessment of this network? 1. The network will work. However, you must configure a second virtual link through router B to ensure there are no routing loops. 2. The network will not work. Area 3 must be directly connected to Area 0. 3.The network will work properly with no redundant hops. 4.network will work. However, it contains sub-optimal routing as packets from router D to router C must transit router A 5.network will not work. A routing loop exists as packets destined for router C from router D must pass through router C twice. Thanks in advance. Regards MK _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF virtual link question
Ditto. No piccy. ""Manish Patel"" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Consider the above OSPF network. You have configured a virtual path to > connect Area 3 with Area 0. What is your assessment of this network? > > 1. The network will work. However, you must configure a second > virtual link through router B to ensure there are no routing loops. > > 2. The network will not work. Area 3 must be directly connected to > Area 0. > > 3.The network will work properly with no redundant hops. > > 4.network will work. However, it contains sub-optimal routing as > packets from router D to router C must transit router A > > 5.network will not work. A routing loop exists as packets destined > for router C from router D must pass through router C twice. > > > > > Thanks in advance. > Regards > MK > > > > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF virtual link question
Consider the above OSPF network. You have configured a virtual path to connect Area 3 with Area 0. What is your assessment of this network? 1. The network will work. However, you must configure a second virtual link through router B to ensure there are no routing loops. 2. The network will not work. Area 3 must be directly connected to Area 0. 3.The network will work properly with no redundant hops. 4.network will work. However, it contains sub-optimal routing as packets from router D to router C must transit router A 5.network will not work. A routing loop exists as packets destined for router C from router D must pass through router C twice. Thanks in advance. Regards MK _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
