> But where is the functionality of the hub defined? In the FR switch? Not on > the hub, as i never had to put any special config there. How come one time i > can use direct DLCI's and the other time i can't?
The hub is the only router having active PVC towards all the other spoke routers. Even if the frame switch is configured to allow full mesh, you are not supposed to use spoke to spoke PVC. Of course it will greatly depend on the requirements given to you... > Wait. Is this how you 'define' the FR hub? Because i can remember some > earlier tasks where i did exactly that, all all pvc communication from then > on went on going through R2 (which had priority 255 and R5 and R6 priority > 0). So they left of the broadcast because they don't want communication, but > it could easily be enabled if i added the broadcast and mapped those ip's > through R2 from then on ? I might be just talking nonsense. To be more precise, it is the way you make OSPF to work on a hub and spokes topology. The frame-relay hub and spoke topology is more defined by the way you setup the PVCs. > Not sure why they set the ospf network type here to broadcast though. They > seem i can set it to anything i want so i'm not sure why they are hellbent on > confusing me :-) It greatly depends on the requirements... But in general, on hub and spoke topologies you have to use OSPF network type broadcast with the tweaking of OSPF priority (0 on spokes and non 0 on the hub) or use OSPF network type non-broadcast with neighbor statement. If the requirements allow both solutions, I usually go for the first one because the timers are faster... Regards, Christophe On 16 Jul 2011, at 18:38, Alef wrote: > > On Jul 16, 2011, at 3:09 PM, marc abel wrote: > >> Make sure that ONLY VLAN 1 can carry untagged frames >> >> This tells a few things. 1. You will be using dot1q trunking since ISL >> tags all frames. 2. Vlan 1 will be the native vlan. 3. Do not tag the >> native vlan. >> > Gotcha. > >> how do we determine when to use a router in FR as a hub >> >> You do what they "tell" you. But often they don't directly tell you. >> There may be clues in the tasks, but often the drawing is the biggest >> clue. In the lab the diagrams are assumed to be correct. If you see a >> difference between the diagram and your startup config, the drawing is >> to be trusted. So look at the drawing, does it show a full mesh? Or >> only connections from the hub to the spokes. > > But where is the functionality of the hub defined? In the FR switch? Not on > the hub, as i never had to put any special config there. How come one time i > can use direct DLCI's and the other time i can't? >> >> How do these configurations prevent from sending data over the mentioned >> DLCI's >> >> They do it by setting the spokes OSPF priority to 0. In OSPF DROthers >> (non DR or BDR) routers do not directly communicate with each other so >> by setting them so that they will never become DR/BDR they ensure that >> OSPF traffic will not flow over thier PVC. I think they left the >> broadcast off in the earlier task because they knew it wouldn't be >> needed, but it isn't explicitly necessary to leave it off. > > Wait. Is this how you 'define' the FR hub? Because i can remember some > earlier tasks where i did exactly that, all all pvc communication from then > on went on going through R2 (which had priority 255 and R5 and R6 priority > 0). So they left of the broadcast because they don't want communication, but > it could easily be enabled if i added the broadcast and mapped those ip's > through R2 from then on ? I might be just talking nonsense. > > Not sure why they set the ospf network type here to broadcast though. They > seem i can set it to anything i want so i'm not sure why they are hellbent on > confusing me :-) >> >> Keep spamming the list! > Thanks again Marc > >> >> On Sat, Jul 16, 2011 at 7:54 AM, Alef <[email protected]> wrote: >>> Usually when setting up the switches and etherchannels it is said as part >>> of the requirement : Make sure that ONLY VLAN 1 can carry untagged frames. >>> What is meant by that exactly ? Does it have to do with the fact that VLAN1 >>> is by default the native van ? >>> >>> and how do we determine when to use a router in FR as a hub. I.e. in the >>> beginning configurations we often have 4 way FR network with R2 as the hub >>> (For example) and R4, R5 and R6 using R2 as the go-to point (502 for .2, .4 >>> , .6. and self-map through any chosen DLCI). But here in the later labs i >>> don't see any of that, and the DLCI's actually map straight to each other >>> and we have separate ones for each router to router pvc. >>> >>> >>> Vol2, Lab 4, task 3.1 >>> How do these configurations prevent from sending data over the mentioned >>> DLCI's ? (We have a full mesh of of DLCI's but R4 and R6 are only supposed >>> to have OSPF traffic passed to R2, not each other). >>> >>> Is it maybe because of the configuration in task 2.1, where we do not >>> specify the broadcast argument between R4 and R6 (that puzzled me). >>> >>> Any help would be appreciated as always, sorry for spamming the list so >>> much! >>> Alef >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, please >>> visit www.ipexpert.com >>> >>> Are you a CCNP or CCIE and looking for a job? Check out >>> www.PlatinumPlacement.com >>> > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
