CertificationZone OSPF I white paper ? [7:23885]
Just finished reading this white paper by Howard and have the following points to raise. Page 8 (A4 wise) last line states : OSPF does not use a transport protocol like UDP or TCP, but runs directly over the Data Link Layer. This looks like a typo as it runs over IP on port 89. Page 13 presents a table of LSA's type and purpose. Type 2 (network) states that this LSA can be generated by any router. With reference to Doyle, Caslow and RFC 1247 it appears that this LSA can only be generated by the DR for multi-access networks. I appear to have confirmed this also in my lab. Referring to the same table : Type 4 (ABR) states that the contents route to 'Area Border Router' whereas Caslow and RFC 1247 states that they route to AS Boundary routers. Phil. Nokia Game is on again. Go to http://uk.yahoo.com/nokiagame/ and join the new all media adventure before November 3rd. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=23885t=23885 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: CertificationZone OSPF I white paper ? [7:23885]
Phil, OSPF does not use tcp or udp, which are IP types 6 17 respectively or vice-versa, it uses IP type 89, not port. Jeff From: Phil Barker Reply-To: Phil Barker To: [EMAIL PROTECTED] Subject: CertificationZone OSPF I white paper ? [7:23885] Date: Tue, 23 Oct 2001 09:20:30 -0400 Just finished reading this white paper by Howard and have the following points to raise. Page 8 (A4 wise) last line states : OSPF does not use a transport protocol like UDP or TCP, but runs directly over the Data Link Layer. This looks like a typo as it runs over IP on port 89. Page 13 presents a table of LSA's type and purpose. Type 2 (network) states that this LSA can be generated by any router. With reference to Doyle, Caslow and RFC 1247 it appears that this LSA can only be generated by the DR for multi-access networks. I appear to have confirmed this also in my lab. Referring to the same table : Type 4 (ABR) states that the contents route to 'Area Border Router' whereas Caslow and RFC 1247 states that they route to AS Boundary routers. Phil. Nokia Game is on again. Go to http://uk.yahoo.com/nokiagame/ and join the new all media adventure before November 3rd. _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=23898t=23885 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: CertificationZone OSPF I white paper ? [7:23885]
We recently had a discussion on Groupstudy as to where in the OSI model routing protocols existed. Essentially, routing protocols are Network layer entities. To quote from the previous discussion: They are layer management protocols at the network layer. This is not covered in the basic OSI Reference Model, but in the Management Annex to it, and the OSI Routeing Architecture document, both from ISO. Just because a protocol is transmitted using a protocol at layer (N) doesn't make the payload protocol layer (N+1). - Howard Berkowitz If we think about it, there are other examples of this being true besides management protocols. It's pretty common to see the session-layer NetBIOS protocol running on top of LLC, for example. (It's sometimes called NetBEUI in this case, but it still has session-layer behavior.) - Priscilla Oppenheimer Pretty awesome having such resources on the list, eh? A long time ago I learned my layers properly, but once I got into looking at sniffer traces, my layers got all mixed up. It's nice having people that keep things straight to set us straight! -- Leigh Anne -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Jeff Smith Sent: Tuesday, October 23, 2001 8:38 AM To: [EMAIL PROTECTED] Subject: Re: CertificationZone OSPF I white paper ? [7:23885] Phil, OSPF does not use tcp or udp, which are IP types 6 17 respectively or vice-versa, it uses IP type 89, not port. Jeff From: Phil Barker Reply-To: Phil Barker To: [EMAIL PROTECTED] Subject: CertificationZone OSPF I white paper ? [7:23885] Date: Tue, 23 Oct 2001 09:20:30 -0400 Just finished reading this white paper by Howard and have the following points to raise. Page 8 (A4 wise) last line states : OSPF does not use a transport protocol like UDP or TCP, but runs directly over the Data Link Layer. This looks like a typo as it runs over IP on port 89. Page 13 presents a table of LSA's type and purpose. Type 2 (network) states that this LSA can be generated by any router. With reference to Doyle, Caslow and RFC 1247 it appears that this LSA can only be generated by the DR for multi-access networks. I appear to have confirmed this also in my lab. Referring to the same table : Type 4 (ABR) states that the contents route to 'Area Border Router' whereas Caslow and RFC 1247 states that they route to AS Boundary routers. Phil. Nokia Game is on again. Go to http://uk.yahoo.com/nokiagame/ and join the new all media adventure before November 3rd. _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=23937t=23885 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: CertificationZone OSPF I white paper ? [7:23885]
Thanks, Phil. I am copying Certzone so the corrections can be made. Just finished reading this white paper by Howard and have the following points to raise. Page 8 (A4 wise) last line states : OSPF does not use a transport protocol like UDP or TCP, but runs directly over the Data Link Layer. This looks like a typo as it runs over IP on port 89. Yes. My fingers were thinking ISIS. Page 13 presents a table of LSA's type and purpose. Type 2 (network) states that this LSA can be generated by any router. With reference to Doyle, Caslow and RFC 1247 it appears that this LSA can only be generated by the DR for multi-access networks. I appear to have confirmed this also in my lab. By any router, I was referring to the box. A box can have zero or more designated routers. I believe the statement is correct that any router -- interior, backbone, ABR, or ASBR can generate it. Incidentally, if you want to check the RFC, use RFC2328, 1247 is ancient. Referring to the same table : Type 4 (ABR) states that the contents route to 'Area Border Router' whereas Caslow and RFC 1247 states that they route to AS Boundary routers. You are correct. Phil. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=23938t=23885 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
