Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ?
At 09:40 AM 8/18/00, Howard C. Berkowitz wrote: Hi Jason: When there is a change a router forwards the LSU to the DR of the multiaccess network using the OSPF multicast 224.0.0.6. The DR acknowledges the receipt of the change and floods the LSU to the others int the multiaccess network using the OSPF multicast address 224.0.0.5. Hope this helps, Carlos Manjarres CCNA Yes, this is true, but not the whole story. As a study topic, why doesn't the reporting router send to the unicast address of the DR? Multicasts imply that more than one destination will listen. Who else would be interested in this update? Why? The backup designated router (BDR) is interested also, in case it has to take over for the DR? Right. When the BDR hears the update, it starts a timer. If the DR doesn't respond when the timer expires, the BDR promotes itself to DR and takes over. ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ?
reponse in-line. - Original Message - From: "Howard C. Berkowitz" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, August 18, 2000 3:40 PM Subject: Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ? Yes, this is true, but not the whole story. As a study topic, why doesn't the reporting router send to the unicast address of the DR? Multicasts imply that more than one destination will listen. Who else would be interested in this update? Why? The Backup Designated Router is interested in the update, because it needs to automatically take over DR duties if the DR fails. If the OSPF neighbors were using the DR's IP address (unicast) instead of the multicast address, they would have to learn the new DR's IP address if the former DR went down. With multicast, the LSU is just sent to 'All Designated Routers', and the routers currently designated as DR and BDR respond to the packet. ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ?
Hi Jason: When there is a change a router forwards the LSU to the DR of the multiaccess network using the OSPF multicast 224.0.0.6. The DR acknowledges the receipt of the change and floods the LSU to the others int the multiaccess network using the OSPF multicast address 224.0.0.5. Hope this helps, Carlos Manjarres CCNA From: "Jason" [EMAIL PROTECTED] Reply-To: "Jason" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: ospf lsu using 224.0.0.5 and 224.0.0.6 ? Date: Fri, 18 Aug 2000 15:12:07 +0800 hi all, anyone knows why during lsu (link state update) of ospf why the router uses ip addr 224.0.0.6, I know this is a multi-cast address but in particular 224.0.0.6. thanks Jason ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ?
hi all, anyone knows why during lsu (link state update) of ospf why the router uses ip addr 224.0.0.6, I know this is a multi-cast address but in particular 224.0.0.6. thanks Jason RFC 2328, section A.1, page 184. Seriously, when you are asking why a protocol does something, the RFC is really the first place to go. I didn't know the specific reference in the OSPF specification, but a search on 224.0.0.6 quickly found it. Hint: OSPF uses two different multicast addresses, and in certain circumstances unicast addresses. The underlying idea is what formally is called "scoping". A broadcast has a scope that includes everyone, while an unicast has a scope of one destination. Think of circumstances where it would be reasonable to have multicasts with more restricted scope than broadcasts. Think of protocol messages that some, not all, OSPF routers need to hear. ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ?
224.0.0.6 is a Well Known Class D address. It is for "All OSPF Designated Routers". Brian On Fri, 18 Aug 2000, Jason wrote: hi all, anyone knows why during lsu (link state update) of ospf why the router uses ip addr 224.0.0.6, I know this is a multi-cast address but in particular 224.0.0.6. thanks Jason ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] --- Brian Feeny, CCNA, CCDA [EMAIL PROTECTED] Network Administrator ShreveNet Inc. (ASN 11881) ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ospf lsu using 224.0.0.5 and 224.0.0.6 ?
At 09:40 AM 8/18/00, Howard C. Berkowitz wrote: Hi Jason: When there is a change a router forwards the LSU to the DR of the multiaccess network using the OSPF multicast 224.0.0.6. The DR acknowledges the receipt of the change and floods the LSU to the others int the multiaccess network using the OSPF multicast address 224.0.0.5. Hope this helps, Carlos Manjarres CCNA Yes, this is true, but not the whole story. As a study topic, why doesn't the reporting router send to the unicast address of the DR? Multicasts imply that more than one destination will listen. Who else would be interested in this update? Why? The backup designated router (BDR) is interested also, in case it has to take over for the DR? From: "Jason" [EMAIL PROTECTED] Reply-To: "Jason" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: ospf lsu using 224.0.0.5 and 224.0.0.6 ? Date: Fri, 18 Aug 2000 15:12:07 +0800 hi all, anyone knows why during lsu (link state update) of ospf why the router uses ip addr 224.0.0.6, I know this is a multi-cast address but in particular 224.0.0.6. thanks Jason ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Priscilla Oppenheimer http://www.priscilla.com ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
