Plesae refer Diagram diag_virtual2.ps Virtual link exercise 2 ====================== Goal ==== OSPF has a heirarchy for routing packets to destinations that are intraarea means within area and those are inter-area means between area. All packets within a area should remain in an area and packets to other area must pass through bacbone area. Even if two area connect to one router, if that router is not a backbone router, the packets must be routed to backbone router to be forwarded to other area. Simple fact that non-backbone router that connects two area does not distribute routes between two area. Now suppose backbone gets partiotined then some of the areas will be unreachable in such circumstances. Virtual links through non-backbone is very usefull in reparing the network, can be seen as a backup path. Another way to see it is a tunnel between area 0 to any other area. Network Configuration: ======================= dexter(config-router)#network 131.252.215.4 0.0.0.0 area 0 dexter(config-router)#network 131.252.215.33 0.0.0.0 area 2 big-baby(config-router)#network 131.252.215.10 0.0.0.0 area 0 big-baby(config-router)#network 131.252.215.82 0.0.0.0 area 1 config........ ! router ospf 100 network 131.252.215.10 0.0.0.0 area 0 network 131.252.215.82 0.0.0.0 area 1 ! yakov(config-router)#network 131.252.215.81 0.0.0.0.0 area 1 yakov(config-router)#network 131.252.215.66 0.0.0.0 area 1 tony(config-router)#network 131.252.215.50 0.0.0.0 area 2 tony(config-router)#network 131.252.215.65 0.0.0.0 area 1 config .... network 131.252.215.50 0.0.0.0 area 2 network 131.252.215.65 0.0.0.0 area 1 ! mrhorse(config-router)#network 131.252.215.35 0.0.0.0 area 2 config... network 131.252.215.35 0.0.0.0 area 2 mrhorse(config)#interface ethernet1 mrhorse(config-if)#shutdown ! interface Ethernet1 description Connected to minshall, port #15 ip address 131.252.215.67 255.255.255.240 no ip directed-broadcast shutdown radia(config-router)#network 131.252.215.34 0.0.0.0 area 2 radia(config-router)#network 131.252.215.34 0.0.0.0 area 2 config ... ! router ospf 100 network 131.252.215.34 0.0.0.0 area 2 network 131.252.215.49 0.0.0.0 area 2 ! To see if the area's are functioning well... ========================================== dexter#ping 131.252.215.81 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 131.252.215.81, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms dexter#ping 131.252.215.82 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 131.252.215.82, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms mrhorse#ping 131.252.215.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 131.252.215.4, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms mrhorse#ping 131.252.215.81 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 131.252.215.81, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms Traceroute to Yakov =================== As said earlier packets to other areas go through the backbone area, hence mrhorse (area1) to yakov(area 2) go through backbone. mrhorse#trace 131.252.215.81 Type escape sequence to abort. Tracing the route to 131.252.215.81 1 131.252.215.33 0 msec 4 msec 0 msec 2 buildme.cs.pdx.edu (131.252.215.10) 4 msec 4 msec 4 msec 3 131.252.215.81 4 msec * 4 msec Do a Backbone partition and see if it works?? ============================================= dexter(config)#interface fastethernet 0/0 dexter(config-if)#shutdown mrhorse#trace 131.252.215.66 Type escape sequence to abort. Tracing the route to 131.252.215.66 1 * * * 2 * * * 3 * * * ......... ......... How to make virtual link ======================= Step 1 ====== Config... tony(config-router)#area 1 virtual-link 131.252.215.82 tony(config-router)#area 2 virtual-link 131.252.215.33 tony(config-router)#^Z Step 2 ====== How to see virtual link... tony#sh ip osp virtual-links 5d08h: %SYS-5-CONFIG_I: Configured from console by consolef virtual-link Virtual Link OSPF_VL1 to router 131.252.215.33 is up Run as demand circuit DoNotAge LSA not allowed (Number of DCbitless LSA is 1). Transit area 2, via interface FastEthernet0/0, Cost of using 2 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:08 Virtual Link OSPF_VL0 to router 131.252.215.82 is up Run as demand circuit DoNotAge LSA not allowed (Number of DCbitless LSA is 1). Transit area 1, via interface FastEthernet0/1, Cost of using 2 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:00 tony#exit DEXTER ====== dexter(config-router)#area 2 virtual-link 131.252.215.65 dexter#sh ip ospf virtual-links 5d06h: %SYS-5-CONFIG_I: Configured from console by console virtual-link Virtual Link OSPF_VL1 to router 131.252.215.65 is up Run as demand circuit DoNotAge LSA not allowed (Number of DCbitless LSA is 3). Transit area 2, via interface FastEthernet0/1, Cost of using 2 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:08 Adjacency State FULL (Hello suppressed) Index 2/4, retransmission queue length 2, number of retransmission 1 First 0x81EDF718(28)/0x0(0) Next 0x81EDF718(28)/0x0(0) Last retransmission scan length is 1, maximum is 1 Last retransmission scan time is 0 msec, maximum is 0 msec Link State retransmission due in 3188 msec BIB-BABY ========== big-baby(config-router)#area 1 virtual-link 131.252.215.65 big-baby#sh ip os virtual-links %SYS-5-CONFIG_I: Configured from console by consolepf vir Virtual Link to router 131.252.215.65 is up Transit area 1, via interface Ethernet0/0, Cost of using 11 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 0:00:00 Adjacency State FULL Backbone partitioning ==================== dexter(config)#interface fastethernet 0/0 dexter(config-if)#shutdown Tests ====== 1. mrhorse to yakov ********************** mrhorse#ping 131.252.215.81 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 131.252.215.81, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms mrhorse#trace 131.252.215.66 Type escape sequence to abort. Tracing the route to 131.252.215.66 1 131.252.215.34 0 msec 0 msec 0 msec 2 131.252.215.50 4 msec 0 msec 4 msec 3 131.252.215.66 4 msec 4 msec * //// mrhorse ---->>> Dexter --->>> Radia --->>> Tony >>>>> Yakov ////