Re: probably simple question about decnet
>On Thu, 5 Apr 2001, Howard C. Berkowitz wrote: > >> Oh, indeed. Also, does anyone remember the interesting interactions >> that would take place when the following conditions applied: >> >> 1. The router ran DECnet >> 2. The router ran IPX >> 3. The router only had serial interfaces >> >> and you didn't get the configuration JUST right? > >Aiye! *runs away screaming* (Haven't run that specific combo, >but I can easily imagine the mess it can be, from configuring X25 IPX >routing the obvious way. Oh, and TR interfaces on some models (AGS+?), >or perhaps some software versions, that would reset when configuring >IPX on them.) You've probably figured out the issue, but for general information: 1. DECnet, when configured and the router is rebooted, ALWAYS starts first and changes ALL MAC adddresses to its algorithmic prediction. 2. IPX (and XNS for that matter, and Banyan under certain circumstances) rely on the availability of a MAC address to create the low-order part of their node addresses. 3. If there was at least one physical LAN interface, that became the source of the MAC address. Otherwise, you had to configure a MAC address in the XXX routing command. If this pseudo-MAC address didn't match the one that DECnet would have created, either DECnet would break or the non-DECnet protocol would break. The situation is even worse when DECnet is adde to the configuratation after one of the MAC-less workgroup protocols already is present. > >Howard, you and I must get together sometime and trade lies and horror >stories. Clearly! _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: probably simple question about decnet
>On Thu, 5 Apr 2001, Howard C. Berkowitz wrote: > >> Oh, indeed. Also, does anyone remember the interesting interactions >> that would take place when the following conditions applied: >> >> 1. The router ran DECnet >> 2. The router ran IPX >> 3. The router only had serial interfaces >> >> and you didn't get the configuration JUST right? > >Aiye! *runs away screaming* (Haven't run that specific combo, >but I can easily imagine the mess it can be, from configuring X25 IPX >routing the obvious way. Oh, and TR interfaces on some models (AGS+?), >or perhaps some software versions, that would reset when configuring >IPX on them.) You've probably figured out the issue, but for general information: 1. DECnet, when configured and the router is rebooted, ALWAYS starts first and changes ALL MAC adddresses to its algorithmic prediction. 2. IPX (and XNS for that matter, and Banyan under certain circumstances) rely on the availability of a MAC address to create the low-order part of their node addresses. 3. If there was at least one physical LAN interface, that became the source of the MAC address. Otherwise, you had to configure a MAC address in the XXX routing command. If this pseudo-MAC address didn't match the one that DECnet would have created, either DECnet would break or the non-DECnet protocol would break. The situation is even worse when DECnet is adde to the configuratation after one of the MAC-less workgroup protocols already is present. > >Howard, you and I must get together sometime and trade lies and horror >stories. where are you, anyway? Clearly! _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: probably simple question about decnet
David, I don't know enough about Decnet to help you but be wary when sniffing that the MAC address that the sniffer picks up is different than what you would expect. Decnet uses an algorithm to convert the "real" MAC address to another. Also I seem to remember a lot of munticasting takes place 1st bytes being 0xAA and 0xAB. Regards, Phil. --- "Hennen, David" <[EMAIL PROTECTED]> wrote: > Hi, I'm wondering how a decnet node finds the > gateway off the local area? > > Example, area is 2, router decnet address is 2.1000. > The decnet address on > the router is changed to 2.1010. Do the nodes, > Alpha box with 2.17 address > for example, figure it out on there own by > listening, does the router > advertise that it's the gateway to other areas, or > do the nodes require > configuration for the change? > > I'm going to be moving a couple of routers running > decnet as well as IP and > would like to avoid problems. I've looked at a few > links on cisco.com and > it sounds like the router makes some type of > advertisement (hello) but I'd > like to be sure. > > thanks if you can help > dave h [EMAIL PROTECTED] Do You Yahoo!? Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk or your free @yahoo.ie address at http://mail.yahoo.ie _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: probably simple question about decnet
>On Wed, 4 Apr 2001, Howard C. Berkowitz wrote: > >> I must say that when Kip first showed me what DECnet did to MAC >> addresses, the voices of the Marx Brothers echoed in my head "Wanna >> buy a DEC?" I forget the names of the developers of this algorithm, >> but one of them used to do an annual apology, saying they just wanted >> to avoid ARP and things...got out of hand. :-) > >ISTR that (back with IOS^H^H^HSystem Software 9.x) life was interesting >for those adventuresome souls who tried running DECNet and XNS on the >same router. Oh, indeed. Also, does anyone remember the interesting interactions that would take place when the following conditions applied: 1. The router ran DECnet 2. The router ran IPX 3. The router only had serial interfaces and you didn't get the configuration JUST right? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: probably simple question about decnet
>I'm surprised you are still using DECnet!? ;-) My DECnet knowledge >is rusty, but here's what I remember from Sniffing DECnet networks: > >There are many hello protocol data units that are sent to >data-link-layer multicast addresses. Routers send hellos to each >other and at least one router per data link sends hellos to all end >nodes. End nodes also send hellos to all routers so the routers >learn who is on their networks. > >All these hellos make DECnet pretty easy to manage and reconfigure. >I don't think you'll have to do anything at the end nodes. > >Many of the "legacy" protocols handled issues such as this better >than the IP protocol family we are stuck with. If you liked DECnet and CLNP (well, ES-IS and IS-IS), you'll probably love stateless autoconfiguration in IPv6. There's a fair similarity between IPv6 neighbor discovery and ES-IS. I must say that when Kip first showed me what DECnet did to MAC addresses, the voices of the Marx Brothers echoed in my head "Wanna buy a DEC?" I forget the names of the developers of this algorithm, but one of them used to do an annual apology, saying they just wanted to avoid ARP and things...got out of hand. :-) > >Priscilla > >>On Wed, 4 Apr 2001, Hennen, David wrote: >> >>> Hi, I'm wondering how a decnet node finds the gateway off the local area? >>> >>> Example, area is 2, router decnet address is 2.1000. The decnet address on >>> the router is changed to 2.1010. Do the nodes, Alpha box with 2.17 address >>> for example, figure it out on there own by listening, does the router >>> advertise that it's the gateway to other areas, or do the nodes require >>> configuration for the change? >>> >>> I'm going to be moving a couple of routers running decnet as well as IP and >>> would like to avoid problems. I've looked at a few links on cisco.com and >>> it sounds like the router makes some type of advertisement (hello) but I'd >>> like to be sure. >>> >>> thanks if you can help >>> dave h >>_ > > > > >Priscilla Oppenheimer >http://www.priscilla.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: probably simple question about decnet
I'm surprised you are still using DECnet!? ;-) My DECnet knowledge is rusty, but here's what I remember from Sniffing DECnet networks: There are many hello protocol data units that are sent to data-link-layer multicast addresses. Routers send hellos to each other and at least one router per data link sends hellos to all end nodes. End nodes also send hellos to all routers so the routers learn who is on their networks. All these hellos make DECnet pretty easy to manage and reconfigure. I don't think you'll have to do anything at the end nodes. Many of the "legacy" protocols handled issues such as this better than the IP protocol family we are stuck with. Priscilla >On Wed, 4 Apr 2001, Hennen, David wrote: > > > Hi, I'm wondering how a decnet node finds the gateway off the local area? > > > > Example, area is 2, router decnet address is 2.1000. The decnet address on > > the router is changed to 2.1010. Do the nodes, Alpha box with 2.17 address > > for example, figure it out on there own by listening, does the router > > advertise that it's the gateway to other areas, or do the nodes require > > configuration for the change? > > > > I'm going to be moving a couple of routers running decnet as well as IP and > > would like to avoid problems. I've looked at a few links on cisco.com and > > it sounds like the router makes some type of advertisement (hello) but I'd > > like to be sure. > > > > thanks if you can help > > dave h >_ Priscilla Oppenheimer http://www.priscilla.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: probably simple question about decnet
I did something similar not too long ago. The nodes and router seem to learn each others addresses possibly through neighborship. The only issue I had was to make sure not to give the router the same address as a node. Jeff On Wed, 4 Apr 2001, Hennen, David wrote: > Hi, I'm wondering how a decnet node finds the gateway off the local area? > > Example, area is 2, router decnet address is 2.1000. The decnet address on > the router is changed to 2.1010. Do the nodes, Alpha box with 2.17 address > for example, figure it out on there own by listening, does the router > advertise that it's the gateway to other areas, or do the nodes require > configuration for the change? > > I'm going to be moving a couple of routers running decnet as well as IP and > would like to avoid problems. I've looked at a few links on cisco.com and > it sounds like the router makes some type of advertisement (hello) but I'd > like to be sure. > > thanks if you can help > dave h _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
