---------- Forwarded message ---------- From: "Arun Arumuganainar" To: "Group Study" Date: Wed, 27 Jul 2005 14:38:00 +0530 Subject: Re: Minimum Number of Routers required for Practice Labs Mailing this for broader interest of the group . The techique can be used if you run short of routers in your lab . With this technique you can create 2 or More routers with in a single physical routers . Using this technique you can very effectively simulate all the back bone or stub routers in your setup with a single physical router with multiple interfaces . Creation Multiple routers using a single router ( For CCIE Practice LAB Purpose only ) : General recommendation : Use this For Back bone or STUB routers in your Topology . e1/0 e1/0 Router1=============Router2 e0/0 e0/0 Here Our topology will look like 2 routers connected back to back via two link . Our Objective is two split the router1 in to two routers namely routera and routerb . When we are done, the topology will look like these . e0/0 e0/0 e1/0 e1/0 routera------router2-------routerb Pls. note : Router A and Router B are actually logical routers created with in router1. You can run same or different protocol on router A and Router B . In our case I have used RIP between router A and Router 2 & OSPF between Router 2 and Router B How to do it ? Step 1: Define a VRF and Apply it on interface : Note : IP Cef is pre-requisite . In case it is not enabled by default enable them using " ip cef " command in the global prompt . Sample Config : For Router A ! ip vrf routera rd 100:100 route-target export 100:100 route-target import 100:100 ! interface Loopback0 ip vrf forwarding routera ip address 10.10.10.1 255.255.255.255 ! interface Ethernet0/0 ip vrf forwarding routera ip address 192.168.1.1 255.255.255.0 ! Note : While configuring VRF first apply vrf and then configure the IP address and not the other way around for Router B ip vrf routerb rd 200:300 route-target export 200:300 route-target import 200:300 ! ! interface Loopback1 ip vrf forwarding routerb ip address 30.30.30.1 255.255.255.255 ! interface Ethernet1/0 ip vrf forwarding routerb ip address 192.168.2.1 255.255.255.0 Config Note : 1) RD is the identifier for Router A and Router B . Pls. give a unique identifier . 2) Ensure that import and export targets are not identical . This will lead to route leaking which we want to avoid Best Practce : Give a unique ID for RD on each VRF and set the import and export targets to RD . STEP 2 : Configure Routing protcols . Here I configured OSPF on RouterA---Router2 and RIP on ROUTER2---RouterB link . I have also did mutual re-distribution between RIP and OSPF at R2 Sample Configs COnfigs on Router 1 !OSPF COnfigs for Router A ! router ospf 100 vrf routera log-adjacency-changes network 0.0.0.0 255.255.255.255 area 100 ! !RIP config for Router B ! router rip ! address-family ipv4 vrf routerb network 30.0.0.0 network 192.168.2.0 no auto-summary exit-address-family ! Configuration on Router 2 Note : Mutual redistribution is enabled router ospf 100 log-adjacency-changes redistribute rip metric 100 metric-type 1 subnets network 20.20.20.0 0.0.0.255 area 100 network 192.168.1.0 0.0.0.255 area 100 ! router rip redistribute ospf 100 metric 8 network 192.168.2.0 ! Verification . Routing Table for Routera ( you have to virew this on Route1 ) Router#sh ip route vrf routera Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is not set 20.0.0.0/32 is subnetted, 1 subnets O 20.20.20.1 [110/11] via 192.168.1.2, 00:02:21, Ethernet0/0 10.0.0.0/32 is subnetted, 1 subnets C 10.10.10.1 is directly connected, Loopback0 C 192.168.1.0/24 is directly connected, Ethernet0/0 O E1 192.168.2.0/24 [110/110] via 192.168.1.2, 00:02:21, Ethernet0/0 O E1 30.0.0.0/8 [110/110] via 192.168.1.2, 00:02:21, Ethernet0/0 Routing Table for Routera ( you have to virew this on Route1 ) Router#sh ip route vrf routerb Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is not set R 20.0.0.0/8 [120/8] via 192.168.2.2, 00:00:01, Ethernet1/0 R 10.0.0.0/8 [120/8] via 192.168.2.2, 00:00:01, Ethernet1/0 R 192.168.1.0/24 [120/8] via 192.168.2.2, 00:00:01, Ethernet1/0 C 192.168.2.0/24 is directly connected, Ethernet1/0 30.0.0.0/32 is subnetted, 1 subnets C 30.30.30.1 is directly connected, Loopback1 Ping Test : Ping from routera to routerb Router# Router#ping vrf routera 30.30.30.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.30.30.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 40/60/100 ms Trace Route from Router A to Router B ( goes via router2) Router#trace vrf routera Protocol [ip]: Target IP address: 30.30.30.1 Source address: Numeric display [n]: Timeout in seconds [3]: Probe count [3]: Minimum Time to Live [1]: Maximum Time to Live [30]: Port Number [33434]: Loose, Strict, Record, Timestamp, Verbose[none]: Type escape sequence to abort. Tracing the route to 30.30.30.1 1 192.168.1.2 40 msec 40 msec 40 msec 2 192.168.2.1 60 msec 40 msec * ----- Original Message ----- From: "Arun Arumuganainar" To: "Shanky" ; "Group Study" Sent: Saturday, July 23, 2005 9:06 PM Subject: Re: Minimum Number of Routers required for Practice Labs > Hi Shanky , > > This is really tricky . Let me suggest few things that you may find useful > > 1) FR switch can be used as a router too . You can use it as core router or > in the Back bone ...No harm ..FR Switching does not interfere with ip > routing . > > 2) You can use Cat Switch as a router too ( may be a back bone router ) . > > 3) Still if your running out of routers . Try doing this . Enable VRF on > interfaces and Runn routing protocol instances . For ex : If a router has > for interfaces and your requirement is 2 routers having 2 interfaces . > > Then you can logically split the router in to two routers by configuring VRF > ( popularly used in MPLS VPN ) . You run different instances of protocol on > each VRF . Believe me ... You can combine all the back bone routers( for ex: > IP EXPERT Topology uses 3 Back bone routers ) in to one and runn 3 > different routing protocols ..as though u have 3 routers .!!! > > Thanks and Regards > Arun