1. Analysed Hello Packets 2. Performance of network with shutdown of one/two i/f of radia 3. Effect of Cost metrix ////////////////////////////////////////////////////////////////////////// dexter#trace big-baby.cs.pdx.edu Translating "big-baby.cs.pdx.edu"...domain server (131.252.208.38) [OK] Type escape sequence to abort. Tracing the route to big-baby.cs.pdx.edu (131.252.215.82) 1 radia.cs.pdx.edu (131.252.215.34) 0 msec 4 msec 0 msec 2 tony.cs.pdx.edu (131.252.215.50) 4 msec 4 msec 0 msec 3 yakov.cs.pdx.edu (131.252.215.66) 4 msec 4 msec 0 msec 4 big-baby.cs.pdx.edu (131.252.215.82) 4 msec * 0 msec dexter#exit radia>enable Password: radia# radia#config t Enter configuration commands, one per line. End with CNTL/Z. radia(config)#interface FastEthernet0/0 radia(config-if)#shutdown radia(config-if)#^Z //////////////////////////////////////////////////////////////////// We shut down one of the interface of radia, we wanted to analyse the effect of this on traceroute from dexter to big-baby, hello packets, data-base entries, neighbor etc. /////////////////////////////////////////////////////////////////// radia# 20:09:16: %SYS-5-CONFIG_I: Configured from console by console 20:09:16: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down 20:09:17: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down radia#show ip ospf interface ///////////////////////////////////////////////////////////////////// FastEthernet0/0 is administratively down, line protocol is down //////////////////////////////////////////////////////////////////// Internet Address 131.252.215.34/28, Area 0 Process ID 100, Router ID 131.252.215.49, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DOWN, Priority 1 No designated router on this network No backup designated router on this network Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 FastEthernet0/1 is up, line protocol is up Internet Address 131.252.215.49/28, Area 1 Process ID 100, Router ID 131.252.215.49, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State BDR, Priority 1 Designated Router (ID) 131.252.215.65, Interface address 131.252.215.50 Backup Designated router (ID) 131.252.215.49, Interface address 131.252.215.49 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:04 Index 1/2, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 4 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 131.252.215.65 (Designated Router) Suppress hello for 0 neighbor(s) radia#show ip ospf neierface Neighbor ID Pri State Dead Time Address Interface 131.252.215.65 1 FULL/DR 00:00:31 131.252.215.50 FastEthernet0/1 ////////////////////////////////////////////////////////////////////// No Neighbor entry for Dexter and Mrhorse ///////////////////////////////////////////////////////////////////// radia#exit dexter>enable Password: Password: dexter#trace big-baby.cs.pdx.edu Type escape sequence to abort. Tracing the route to big-baby.cs.pdx.edu (131.252.215.82) 1 mrhorse.cat.pdx.edu (131.252.215.35) 4 msec 0 msec 4 msec 2 yakov.cs.pdx.edu (131.252.215.66) 8 msec 0 msec 4 msec 3 big-baby.cs.pdx.edu (131.252.215.82) 4 msec * 0 msec dexter#exit ///////////////////////////////////////////////////////////////////////// Earlier traceroute was through Radia now it is taking other path //////////////////////////////////////////////////////////////////////// Analysis of Hello Packets ======================== //////////////////////////////////////////////////////////////// Befor this we shutdown both the i/f of radia and it is isolated ////////////////////////////////////////////////////////////// radia#traceddexter.cs.pdx.edu Translating "dexter.cs.pdx.edu"...domain server (131.252.208.38) (131.252.208.58) % Unrecognized host or address. radia# radia#trace tony.cs.pdx.edu Translating "tony.cs.pdx.edu"...domain server (131.252.208.38) (131.252.208.58) % Unrecognized host or address. radia#config t Enter configuration commands, one per line. End with CNTL/Z. radia(config)#interface fastethernet 0/1 radia(config-if)#no shutdown radia(config-if)#^Z ////////////////////////////////////////////// one of the interface is up ///////////////////////////////////////////// OSPF: Interface FastEthernet0/1 going Up OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing %SYS-5-CONFIG_I: Configured from console by console radia# OSPF: Build router LSA for area 1, router ID 131.252.215.49, seq 0x80000001 OSPF: Build router LSA for area 0, router ID 131.252.215.49, seq 0x80000001 %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state INIT /******it is a initial state and there is no bidirectional communication yet ***/ OSPF: 2 Way Communication to 131.252.215.65 on FastEthernet0/1, state 2WAY OSPF: Nbr state is 2WAY /***got 2 Way state with Tony ***/ OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY /****Notice in early DBD no 2WAY but Seq # same ****/ OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY OSPF: end of Wait on interface FastEthernet0/1 OSPF: DR/BDR election on FastEthernet0/1 OSPF: Elect BDR 131.252.215.49 OSPF: Elect DR 131.252.215.65 OSPF: Elect BDR 131.252.215.49 OSPF: Elect DR 131.252.215.65 DR: 131.252.215.65 (Id) BDR: 131.252.215.49 (Id) OSPF: Send DBD to 131.252.215.65 on FastEthernet0/1 seq 0x8EE opt 0x2 flag 0x7 len 32 OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: Neighbor change Event on interface FastEthernet0/1 OSPF: DR/BDR election on FastEthernet0/1 OSPF: Elect BDR 131.252.215.49 OSPF: Elect DR 131.252.215.65 DR: 131.252.215.65 (Id) BDR: 131.252.215.49 (Id) OSPF: End of hello processing /***Till now both are saying that they are master but election would be in EXSTART as this is the first step in creating Adj between two neighboring routers also deciding initial sequence Number ****/ OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x7 len 32 state EXSTART OSPF: NBR Negotiation Done. We are the SLAVE /***this is the Exchange state and TONY is describing entire link state database ****/ /***Seq number will be updated by Master as only one DBD pkt outstanding packet at any time *****/ OSPF: Send DBD to 131.252.215.65 on FastEthernet0/1 seq 0x107F opt 0x2 flag 0x2 len 272 OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x1080 opt 0x2 flag 0x3 len 312 state EXCHANGE OSPF: Send DBD to 131.252.215.65 on FastEthernet0/1 seq 0x1080 opt 0x2 flag 0x0 len 32 OSPF: Database request to 131.252.215.65 OSPF: sent LS REQ packet to 131.252.215.50, length 108 ///Request packet about more recent advertisement's /////// OSPF: Rcv DBD from 131.252.215.65 on FastEthernet0/1 seq 0x1081 opt 0x2 flag 0x1 len 32 state EXCHANGE /////Seq # + 1 by Tony /////// OSPF: Exchange Done with 131.252.215.65 on FastEthernet0/1 OSPF: Send DBD to 131.252.215.65 on FastEthernet0/1 seq 0x1081 opt 0x2 flag 0x0 len 32 OSPF: Build router LSA for area 1, router ID 131.252.215.49, seq 0x80000005 OSPF: Synchronized with 131.252.215.65 on FastEthernet0/1, state FULL ///Now Radia and Tony are fully adjacent //////// OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Build router LSA for area 1, router ID 131.252.215.49, seq 0x80000006 OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing radia#trace dexter.cs.pdx.edu Translating "dexter.cs.pdx.edu"...domain server (131.252.208.38) [OK] Type escape sequence to abort. Tracing the route to dexter.cs.pdx.edu (131.252.215.4) 1 tony.cs.pdx.edu (131.252.215.50) 0 msec 0 msec 4 msec 2 mrhorse.cat.pdx.edu (131.252.215.67) 4 msec 4 msec 4 msec 3 131.252.215.33 0 msec * 0 msec radia# OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processingtrace dexter.cs.pdx.edu Type escape sequence to abort. Tracing the route to dexter.cs.pdx.edu (131.252.215.4) 1 tony.cs.pdx.edu (131.252.215.50) 0 msec 4 msec 0 msec 2 mrhorse.cat.pdx.edu (131.252.215.67) 4 msec 4 msec 4 msec 3 131.252.215.33 0 msec OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing * 0 msec radia# radia# radia# radia# radia#conf t Enter configuration commands, one per line. End with CNTL/Z. radia(config)# OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processinginterface fastethernet 0/0 radia(config-if)#no OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing shutdown radia(config-if)#^Z radia# OSPF: Interface FastEthernet0/0 going Up OSPF: Build router LSA for area 0, router ID 131.252.215.49, seq 0x80000002 OSPF: Build router LSA for area 1, router ID 131.252.215.49, seq 0x80000007 %SYS-5-CONFIG_I: Configured from console by console %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up /////we are bringing up another interface ///////////// OSPF: Rcv hello from 131.252.215.67 area 0 from FastEthernet0/0 131.252.215.35 OSPF: 2 Way Communication to 131.252.215.67 on FastEthernet0/0, state 2WAY OSPF: End of hello processing OSPF: Rcv DBD from 131.252.215.67 on FastEthernet0/0 seq 0x23CD opt 0x2 flag 0x7 len 32 state 2WAY OSPF: Nbr state is 2WAY OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.33 area 0 from FastEthernet0/0 131.252.215.33 OSPF: 2 Way Communication to 131.252.215.33 on FastEthernet0/0, state 2WAY OSPF: Backup seen Event before WAIT timer on FastEthernet0/0 OSPF: DR/BDR election on FastEthernet0/0 OSPF: Elect BDR 131.252.215.33 OSPF: Elect DR 131.252.215.67 DR: 131.252.215.67 (Id) BDR: 131.252.215.33 (Id) OSPF: Send DBD to 131.252.215.33 on FastEthernet0/0 seq 0x1D13 opt 0x2 flag 0x7 len 32 OSPF: Send DBD to 131.252.215.67 on FastEthernet0/0 seq 0x1C15 opt 0x2 flag 0x7 len 32 OSPF: End of hello processing OSPF: Rcv DBD from 131.252.215.67 on FastEthernet0/0 seq 0x23CD opt 0x2 flag 0x7 len 32 state EXSTART OSPF: NBR Negotiation Done. We are the SLAVE OSPF: Send DBD to 131.252.215.67 on FastEthernet0/0 seq 0x23CD opt 0x2 flag 0x2 len 272 OSPF: Rcv DBD from 131.252.215.67 on FastEthernet0/0 seq 0x23CE opt 0x2 flag 0x3 len 212 state EXCHANGE OSPF: Send DBD to 131.252.215.67 on FastEthernet0/0 seq 0x23CE opt 0x2 flag 0x0 len 32 OSPF: Database request to 131.252.215.67 OSPF: sent LS REQ packet to 131.252.215.35, length 60 OSPF: Rcv DBD from 131.252.215.67 on FastEthernet0/0 seq 0x23CF opt 0x2 flag 0x1 len 32 state EXCHANGE OSPF: Exchange Done with 131.252.215.67 on FastEthernet0/0 OSPF: Send DBD to 131.252.215.67 on FastEthernet0/0 seq 0x23CF opt 0x2 flag 0x0 len 32 OSPF: Synchronized with 131.252.215.67 on FastEthernet0/0, state FULL OSPF: Build router LSA for area 0, router ID 131.252.215.49, seq 0x80000003 /****Radia is keeping it's own Seq Number /// OSPF: Retransmitting DBD to 131.252.215.33 on FastEthernet0/0 OSPF: Send DBD to 131.252.215.33 on FastEthernet0/0 seq 0x1D13 opt 0x2 flag 0x7 len 32 OSPF: Rcv DBD from 131.252.215.33 on FastEthernet0/0 seq 0xC55 opt 0x42 flag 0x7 len 32 state EXSTART OSPF: First DBD and we are not SLAVE OSPF: Rcv DBD from 131.252.215.33 on FastEthernet0/0 seq 0x1D13 opt 0x42 flag 0x2 len 292 state EXSTART OSPF: NBR Negotiation Done. We are the MASTER //// with Dexter radia wins because of higher Ip address ///// OSPF: Send DBD to 131.252.215.33 on FastEthernet0/0 seq 0x1D14 opt 0x2 flag 0x3 len 292 OSPF: Database request to 131.252.215.33 OSPF: sent LS REQ packet to 131.252.215.33, length 12 OSPF: Rcv DBD from 131.252.215.33 on FastEthernet0/0 seq 0x1D14 opt 0x42 flag 0x0 len 32 state EXCHANGE OSPF: Send DBD to 131.252.215.33 on FastEthernet0/0 seq 0x1D15 opt 0x2 flag 0x1 len 32 OSPF: Rcv DBD from 131.252.215.33 on FastEthernet0/0 seq 0x1D15 opt 0x42 flag 0x0 len 32 state EXCHANGE OSPF: Exchange Done with 131.252.215.33 on FastEthernet0/0 OSPF: Synchronized with 131.252.215.33 on FastEthernet0/0, state FULL /////Fully adjacent with Dexter /////// OSPF: Rcv hello from 131.252.215.67 area 0 from FastEthernet0/0 131.252.215.35 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.33 area 0 from FastEthernet0/0 131.252.215.33 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.67 area 0 from FastEthernet0/0 131.252.215.35 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processing OSPF: Rcv hello from 131.252.215.33 area 0 from FastEthernet0/0 131.252.215.33 OSPF: End of hello processing radia#no OSPF: Rcv hello from 131.252.215.67 area 0 from FastEthernet0/0 131.252.215.35 OSPF: End of hello processingdeb OSPF: Rcv hello from 131.252.215.65 area 1 from FastEthernet0/1 131.252.215.50 OSPF: End of hello processingug ip ospf OSPF: Rcv hello from 131.252.215.33 area 0 from FastEthernet0/0 131.252.215.33 OSPF: End of hello processingadj OSPF adjacency events debugging is off radia#exit //////////////////////////////////////////////////////////////////////////////// Changing the cost of an interface ================================= The 'show ip ospf interface' command shows that mrhorse and big-baby have a default cost metric of 10 while all the other routers have a cost metric of 1. OSPF automatically calculates the default cost metric for an interface according to the bandwidth of an interface using the formula: cost = 10^8 / bandwidth The cost of routing a packet throiugh a particular interface can also be explicitly configured for each interface of a router by using the following commands: >interface Ethernet0 >ip ospf cost 1 where Ethernet0 is the interface for which the cost is being changed and 1 is the value that the interface is to be configured with. The cost of routing a packet through a particular interface can be changed back to the default by using the following ospf commands: >interface Ethernet0 >no ip ospf cost /******************************************************************************/ Traceroute from big-baby to dexter with default cost metric =========================================================== big-baby#trace dexter Type escape sequence to abort. Tracing the route to dexter.cs.pdx.edu (131.252.215.4) 1 131.252.215.81 0 msec 0 msec 0 msec 2 131.252.215.65 4 msec 0 msec 4 msec 3 131.252.215.49 4 msec 4 msec 4 msec 4 131.252.215.33 0 msec * 0 msec Change cost of both interfaces of mrhorse ========================================= mrhorse#config t Enter configuration commands, one per line. End with CNTL/Z. mrhorse(config)#interface ethernet 0 mrhorse(config-if)#ip ospf cost 1 mrhorse(config-if)#^Z mrhorse#config t Enter configuration commands, one per line. End with CNTL/Z. mrhorse(config)#interface ethernet 1 mrhorse(config-if)#ip ospf cost 1 mrhorse(config-if)#^Z Traceroute from big-baby to dexter with new cost metrics ======================================================== big-baby#trace dexter Type escape sequence to abort. Tracing the route to dexter.cs.pdx.edu (131.252.215.4) 1 131.252.215.81 0 msec 4 msec 0 msec 2 131.252.215.67 4 msec 4 msec 4 msec 3 131.252.215.33 4 msec * 0 msec This time the path taken was through mrhorse. To get from big-baby to dexter through mrhorse takes only two hops of cost 1 each while to get from big-baby to dexter through tony and Radia takes 3 hops of cost 1 each, hence the path chosen was through mrhorse. /******************************************************************************/ /******************************************************************************/ /******************************************************************************/