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>