not that I enjoy rattling around CCO researching obscure topics, but I have had two different customers raise the specter of multilink ppp (use multiple T1's to increase bandwidth without having to resort to the expense of ATM or DS3 )
CCO tends to be rather obscure on this topic, with most of the coverage devoted to ISDN links for dial access. see http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/dial ts_c/dtsprt4/dcdppp.htm#xtocid44 as an example. in any case, the basic case of 2 serial links between two routers is relatively simple, provide you follow the setup procedure carefully. otherwise you end up in reload hell ;-> But then I got curious about the case where you have three routers in a hub and spoke. Two serial links to one spoke, two serial links to the other. This got to be rather involved, and the final working result has left me with a situation I can't explain rationally. the process: Spoke router 1) multilink virtual-template x 2) interface virtual-template x ip address x.x.x.x m.m.m.m ppp multilink 3) interface serial 0 encap ppp ppp multilink 4) interface serial 1 encap ppp ppp multilink Hub router 1) multilink virtual-template x (apparently you can only have one of these commands, even though x may have a value of 1-25) 2) interface multilink 1 ip address x.x.x.x m.m.m.m ppp multilink multilink-group 1 3) interface serial 0 encap ppp ppp multilink multilink-group 1 4) interface serial 1 encap ppp ppp multilink multilink-group 1 5) interface multilink 2 ip address x.x.x.x m.m.m.m ppp multilink multilink-group 2 6) interface serial 2 encap ppp ppp multilink multilink-group 2 7) interface serial 3 encap ppp ppp multilink multilink-group 2 this configuration works. but here is the kicker. in the following routing table, note the /32's associated with the virtual-access interface on the spoke router. the hub router shows /32's associated with the multilink interfaces. Spoke router Gateway of last resort is not set 172.21.0.0/24 is subnetted, 2 subnets C 172.21.1.0 is directly connected, Loopback0 C 172.21.2.0 is directly connected, Loopback1 22.0.0.0/8 is variably subnetted, 2 subnets, 2 masks D 22.29.1.0/24 [90/5948928] via 26.44.1.2, 00:20:10, Virtual-Access1 D 22.29.1.1/32 [90/5948928] via 26.44.1.2, 00:20:10, Virtual-Access1 129.7.0.0/24 is subnetted, 2 subnets D 129.7.22.0 [90/6076928] via 26.44.1.2, 00:20:10, Virtual-Access1 D 129.7.44.0 [90/6076928] via 26.44.1.2, 00:20:11, Virtual-Access1 26.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 26.44.1.2/32 is directly connected, Virtual-Access1 C 26.44.1.0/24 is directly connected, Virtual-Access1 Hub router Gateway of last resort is not set 172.21.0.0/24 is subnetted, 2 subnets D 172.21.1.0 [90/3312896] via 26.44.1.1, 00:22:31, Multilink1 D 172.21.2.0 [90/3312896] via 26.44.1.1, 00:22:31, Multilink1 22.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 22.29.1.0/24 is directly connected, Multilink2 C 22.29.1.1/32 is directly connected, Multilink2 129.7.0.0/24 is subnetted, 2 subnets D 129.7.22.0 [90/3312896] via 22.29.1.1, 05:09:21, Multilink2 D 129.7.44.0 [90/3312896] via 22.29.1.1, 05:09:22, Multilink2 26.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 26.44.1.1/32 is directly connected, Multilink1 C 26.44.1.0/24 is directly connected, Multilink1 I'm at a loss as to why there is a /32 at all. interface Multilink1 ip address 26.44.1.2 255.255.255.0 no cdp enable ppp multilink multilink-group 1 not that multilink ppp is a cutting edge technology. but I am always curious about how things really work. anyone use this in real world? if so, what kinds of results are you seeing? thanks Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=39961&t=39961 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
