BGP Lab Exercise 2
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1.  We're now going to extend the BGP network to something a little more realistic.
   You should start by meeting the rest of the routers in your group.  You will need 
   to work together for the remainder of this lab.


2.  Look through the address space that you have.  You will need to decide certain things.
   What size IPv4 address block should you use?
   IPv4 Address Block for the Point to Point Link:
   IPv4 Address for your side of the link:
   IPv4 Address for the other side of the link:

   Likewise, for the IPv6 addressing for the point to point link,
   agree what address block you will take.

   What size IPv6 address block should you use?
   IPv6 Address Block for the Point to Point Link:
   IPv6 Address for your side of the link:
   IPv6 Address for the other side of the link:


3.  Write down the AS numbers of the network(s) that you are connecting to:

   Upstream AS Number:
   Your AS Number:
   Peer AS Number:

   Do this for every peer that you have to setup.  It is handy to have this information.
   Which of these are iBGP and which of these are eBGP peers?


4.  Identify and configure the iBGP peers.  Remember that these need to be 
   configured as a full-mesh.  Configure the full mesh and confirm that you 
   can see the "clients" from each router.
   At the end of the exercise, each FreeBSD PC should be pingable from the other PCs.


5.  By now you should know that you have to configure your IGP (in this case, OSPF) to
   get your iBGP to work.
5.1  Make sure that you, as a group, understand the dependency that iBGP has on your IGP.
5.2  Ensure that you have all your OSPF neighbours and all the relevant routers visible
   via OSPF.  How many neighbours will you expect to see?   How many other routers? 


6.  You were taught that iBGP is done between loopback addresses.
6.1  Why is it important that we do this?
6.2  What does the next-hop-self command do, and why do you need it here (if at all)?
6.3  How do we know how to get to the next hop address (the loopback) of our iBGP peers?


7.  Check the BGP process for IPv4 using "sh ip bgp" and sub commands
   to see what prefixes you are receiving from your neighbouring AS.
   For IPv6, remember that the syntax is "sh bgp ipv6" and sub
   commands.  Note that "sh bgp ipv4" will also work to show you the
   state of the IPv4 BGP table.

8.  What routes do you see?  What paths are available?  Describe what
   you see in the space below:




9.  eBGP to some of the upstream ASes will need to be configured to a peer AS.
   Use the examples in the previous exercise to guide you.  Don't forget
   to set up both IPv4 and IPv6 BGP peerings.


10.  What *new* routes do you see?  What paths are available?  Describe what
   you see in the space below:





11.  We are now at the stage where we are talking BGP with our upstream
   ISP and iBGP with the neighbouring router in our locality.  We are
   using both IPv4 and IPv6 for this peering.  Note that this is the
   common way that ISPs configure IPv4 and IPv6 peerings - whatever is
   done with IPv4 is repeated with IPv6.

   But we have no filters and as you saw in the previous step.  We are
   now going to fix this using two different methods in the upcoming 
   exercises.