TLEN5370 Lab 2

TLEN5370 - Lab 2 Logistics Choose a console and two routers which will be refered to as odd and even for the remainder of the lab. Write erase the routers and start from scratch with a default config. Connect your routers with an ethernet switch and be able to telnet from your terminal to each router. (no console cable after initial setup!)

No matter what the Halabi tutorial has in it -- do *NOT* use any 'access-list' or 'distribute-list' Make your life easier and use 'ip prefix-list' configurations instead. Objectives Form an eBGP session between two routers. Form an eBGP session between the loopbacks of two routers. Match and Set BGP Attributes Outbound on Cisco Match and Set BGP Attributes Inbound on Cisco Fully understand next-hop, next-hop-self, and glue networks. Use a route-map on a static pullup and outbound policy. Match and Set BGP Attributes Outbound on Juniper Match and Set BGP Attributes Inbound on Juniper Useful Cisco Commands show ip bgp summary show ip bgp a.b.c.d show ip bgp neighbor a.b.c.d advertised-routes show ip bgp neighbor a.b.c.d received-routes show ip bgp neighbor a.b.c.d routes show ip route show ip route a.b.c.d clear ip bgp a.b.c.d clear ip bgp a.b.c.d soft show running-config Objective 1 Establish an eBGP peering session between your two routers using the ethernet0 IPs. Be sure to turn on 'no synchronization' Question 1.1 - How do you know your BGP session is established? Where do you look for this? Question 1.2 - Do you see any routes being exchanged? Where do you look for this? Run the following commands on your 'odd' router then reset/clear the session. debug ip bgp events debut ip bgp keepalives debug ip bgp updates term mon To turn off debug you would type 'no debug all' Question 1.3 - Observe and log the debug messages for 1 minute then shutdown the session 'neighbor a.b.c.d shut' on the 'even' router. Turn in the log and a description of what each debug message means in your own words. Question 1.4 - Do the same thing but instead of shutting the connection...unplug the even router (power or ethernet.) What happens? What is different from just shutting the session? Question 1.5 - Why would you never turn on 'debug ip bgp updates' on a router receiving full internet routers? Create a loopback on your 'odd' router that is a different subnet from your ethernet interface. Question 1.6 - Can you reach it (ping a.b.c.d) from your 'even' router? Why not? Question 1.7 - What should you do to make this reachable? No IGP or Static allowed! Question 1.8 - Observing the debug output. Make this route inaccessible and accessible several times while logging the debug output. Turn in the log and a description of what each debug message corresponding to the route installation/withdrawal means. Type 'no router bgp MY-AS' and 'no debug all' on both routers. OBJECTIVE 2 Establish an eBGP peering session between your two routers using loopbacks. Create a loopback on the 'even' router using the same instructions from objective 1. Establish an eBGP peering session between the router loopbacks. Question 2.1 - What 2 BGP commands do you need to add that weren't needed in Objective 1? Question 2.2 - What other command do you need? (think reachability) Question 2.3 - Turn in a log file showing the established session and relevant configuration. Question 2.4 - Why would you ever do eBGP multihop on an eBGP session? Type 'no router bgp MY-AS' OBJECTIVE 3 Match and set outbound route attributes using a single route-map. Create 4 additional /32 loopbacks on your 'odd' router. Bring up a BGP session using the ethernet addresses. Make sure the 'even' router can get to all loopbacks of the 'odd' router. Using a single route-map set the following attributes outbound: Match loopback1 and set as-path to prepend ODD-AS twice. Match loopback2 and set community to MY-AS:1 (be sure you are sending communities) Match loopback3 and set as-path to prepend ODD-AS three times. Match loopback4 and set metric to 50. Match loopback5 and deny the route. Match any prefix and accept. Question 3.1-5 - Using 'show ip bgp a.b.c.d' show on your 'even' router that each attribute has been modified as desired. Question 3.6 - Turn-in a copy of your route-map and associated lists. OBJECTIVE 4 Match and set inbound route attributes using a single route-map. Now set the attributes of the inbound routes on your 'even' router. Using a single route-map set the following attributes inbound: Match as-path ODD-AS_ODD-AS_ODD-AS and set the weigth to 150. Match the community ODD-AS:1 and set the local-pref to 200. Match the as-path ODD-AS_ODD-AS_ODD-AS_ODD-AS and set the metric to 50. Match the route from loopback4 and deny the route. Match any prefix and accept. Question 4.1-5 - Using 'show ip bgp a.b.c.d' show on your 'even' router that each attribute has been modified as desired. Question 4.6 - Turn in a copy of your route-map and associated lists. OBJECTIVE 5 Fully understand next-hop, next-hop-self, and glue networks. Remove the extra loopbacks from objectives 3 and 4. Configure a new router attached to ODD via a point to point link (for lab purposes we can name it 'ODDER') Configure eBGP between the interfaces of EVEN and ODD. Configure iBGP between the loopbacks of ODD and ODDER. You will need an IGP of some sort running as well. Pull up a route with a network statement on EVEN. Verify this is advertised to ODD. Question 5.1 - Is the route from EVEN advertised to ODDER? Show this. Question 5.2 - Is the route from EVEN usable on ODD? Why or why not? Question 5.3 - Is the route from EVEN usable on ODDER? Why or why not? Add the glue network between EVEN and ODD to the IGP of ODD. Question 5.4 - Any special considerations for the ODD interface facing EVEN? Question 5.5 - Does this solve anything? Why or why not? Question 5.6 - If you had 5000 point to point customer links what should you consider? Remove the glue network between EVEN and ODD from the IGP of ODD. Configure the iBGP between ODD and ODDER to next-hop-self. Question 5.7 - Does this solve anything? Why or why not? Question 5.8 - Did this break anything? (consider forwarding ability vs reachability) OBJECTIVE 6 Use a route-map on a static pullup and outbound policy. Pull up two /8 routes with network statements on ODDER. Verify these are advertised to EVEN. Question 6.1 - Show the config needed to pullup these routes in BGP statically. Question 6.2 - Show the config needed to tag the first route with a community ODD-AS:123 and set the origin to Internal/IGP. Question 6.3 - Show the config needed to tag the second router with a community ODD-AS:666 and set the origin to Internal/IGP. Question 6.4 - Show the config to create an export (outbound) policy on ODD towards EVEN to advertise routes tagged with ODD-AS:123 and no others. OBJECTIVE 7 - OPTIONAL BUT ENCOURAGED Juniper Outbound Policy Replace one of your routers with a Juniper Create 5 /32 loopbacks on your Juniper router (i.e. same as objective 3) Bring up a BGP session using the ethernet addresses. Make sure the cisco router can get to all loopbacks of the juniper router. Using a single route-map set the following attributes outbound: Match loopback1 and set as-path to prepend ODD-AS twice. Match loopback2 and set community to MY-AS:1 (be sure you are sending communities) Match loopback3 and set as-path to prepend ODD-AS three times. Match loopback4 and set metric to 50. Match loopback5 and deny the route. Match any prefix and accept. Question 7.1-5 - Using 'show ip bgp a.b.c.d' show on your cisco router that each attribute has been modified as desired. Question 7.6 - Turn-in a copy of your policy-statement and associated lists. OBJECTIVE 8 - OPTIONAL BUT ENCOURAGED Juniper Inbound Policy Turn things around and advertise routes to your Juniper now (use the cisco configs from objective 4) Using policy-statements under policy options set the following attributes inbound: Match as-path ODD-AS_ODD-AS_ODD-AS and set the weigth to 150. Match the community ODD-AS:1 and set the local-pref to 200. Match the as-path ODD-AS_ODD-AS_ODD-AS_ODD-AS and set the metric to 50. Match the route from loopback4 and deny the route. Match any prefix and accept. Question 8.1-5 - Using 'show ip bgp a.b.c.d' show on your juniper router that each attribute has been modified as desired. Question 8.6 - Turn in a copy of your route-map and associated lists. OBJECTIVE 9 Wrap up Question 9.1 - What did you learn from this lab? Question 9.2 - What was the least useful part of this lab? Question 9.3 - What was the most useful part of this lab>