HI, this might seem a very basic question but i m a bit confused, i was reading jeff doyle 1 first edition, in chapter 11 under the topic of "Redistributing from classless to classfull Protocols" (FIG 11.12) he has given example ofa router with 4 interfaces, e1 = 192.168.100.129/27
e0 = 192.168.100.97/27, s 0 = 192.168.100.9/30, s 1 = 192.168.100.5/30
he said the subnet of s 0 which is of mask 30 is not advertised out e1 and e0 since it cannot use the 27 bit mask to derive 30 bit subnets, and it cannot use 30 bit mask to derive 27-bit subnets, i m a bit confused here why it cant derive the masks ? all i know abt classful is that subnet mask is not send in updates, is that the only rule shall i be concerned abt? or this example is saying something more that i shuld know ?? plz tell me either refer me any doc or plz explain
So the router knows that it has subnets 192.168.100.4 and 192.168.100.8. If the router DID advertise the serial subnets to its neighbor on E0 then the neighbor receives 192.168.100.4 and since the neighbor did not receive advertisement of the mask it will assume that its own mask should work (/27). But there are a couple of problems with this. First 192.168.100.4 is not a valid subnet address with a /27 mask. Second (and more serious) the neighbor would believe that 192.168.100.21 was in the subnet of the neighbor but it is not.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.