CSC 425 Problems with Solutions, Spring 2008

ogee arta . 4 CSC425 1, Problems am aE 8 fA NO AOE! 1. The WAN presented in the figure below uses virtual circuits. t itch 1 | [=] Dr. H. Maalouf Give the virtual circuit switching tables in each switch (1 to 4) after cach of the following connections is established 1. Host A connects to host B. 2. Host C connects to host G. 3. Host E connects to host J. 4. Host D connects to host B. Assume that the connections stay up-during the period of observation. Also assume that the virtual circuit identifier (VCD allocation always picks the lowest unused identifier on each outbound link.If a particular connection does not affect a particular switch; leave the corresponding row empty. Switch | | Input port Input VCI {Output port Output VCI Ato B | i) { al | l CioG 4 t 2. { Etol = —_ _ — DtoB | 2 wR L 2 Switch 2 Input port Input YCI Output port Output VCI Ato B —_— —_— — — CtoG o t Z t Etol 2 2 | ka [ DtoB 1 l iD) 2 Switch 3 Input port Input YCI Ourput port Output ¥CI AtoB —_ _ —— = CtoG | ! { E tol Ll 2. DtoB o— —_ I —_ —_— Switch 4 Input port Input VCI Output port Output VCL AtoB _ —_ — —_ CtoG —_— _ _— — Etol L eo) t DtoB — = — —_ 2. Consider the following network consisting of two three-station Ethemets attached via an IP router. Host 4 through F have MAC addresses of aaa, bbb, ..., fff respectively. Router port 1 has MAC address yyy, port 2 has MAC address zzz. The host id is shown above each host, the netid below the Ethernet. e Give the ARP cache for station C assuming that C has recently communicated with all other stations. e Give the routing table for the router. « IfA sends a packet to D, explain what takes place and sketch the packet. Identify the contents of the “important” address fields. 001 A al 001.128.123 oo 01 178.124_ _ ARP Table Por C V128.124,4 | yag.1234 a4 Aa. Cloke _ M12€024%.9 F.42e.123.4 ddd 222z