Tutorial Part 2A: Running XIA over GENI

XIA GENI Tutorial

Overview

In this part of the tutorial we will walk you through setting up a simple 5 node topology and then running a simple file transfer across the network. We show how XIA enables opportunistic file caching using Content Identifiers (CIDs) by fetching the same content from (now populated) content caches within the network. We'll see how these transfers work in detail by examining packets on the wire.

Start and Test the Network

Once all of the network nodes are in the ready state we can boot the xia network.

Here's our 5 node topology once again:

1. Check the status of your sliver
   Creating the XIA network will take approximately 15 minutes.

   readyToLogin slicename --useSliceAggregates --no-keys
   

   Once all the nodes are up and running the output from readyToLogin should resemble the following:

2. Switch to the tutorial specific .ssh/config file.
   • Save your present config file

     mv ~/.ssh/config ~/.ssh/config.keep
     

   • Create a tutorial specific config file and copy it to the .ssh directory.

     readyToLogin  --useSliceAggregates -o slicename
     mv ./sshconfig.txt ~/.ssh/config
     

3. Add private key (associated with your public key on the GENI portal) to ssh-agent so ssh can forward your credentials.

   ssh-add /path/to/private_key
   

4. Log into router1
   

   ssh -A router1
   

5. Boot the network
   

   cd /xia-core
   tutorial/xboot
   

   Once you see many lines that say "running" at the end, hit enter.
6. Examine the routing table on router1

   bin/xroute
   

   The output should look like the following:

   The routing table output shows the routes for each of the 5 default principal types supported by XIA. Notice specific routes for each device connected directly to router1, as well as some control router (e.g., routes with negative port values) and default routes. In Part 2B of the tutorial we will add a new principal type to this forwarding table.
   
   Run the following command to see the routing table without using human-readable names

   bin/xroute -v
   

   It will look like:

7. We're going to transfer a file from server0 to host0 using an ftp-like protocol. To do this over XIA, we first send a request to an service (SID) residing on sever0 that returns us a list of content (CIDs) to fetch. We then request these CIDs from the network (providing a fallback to the HID for server0). Since the network does not know about these CIDs, the fallback to server0 is used and the content is returned from server0. Thus all content is transferred from server0. We will verify this by using tcpdump on the link between router1 and server0.
   • Run tcpdump on router1.

     sudo tcpdump -i `ifconfig | awk '/10.10.3.1/ {print $1}' RS="\n\n"` "not ether dst ff:ff:ff:ff:ff:ff"
     

     This monitors all traffic between router1 and server0, ignoring broadcast traffic.
   • Open a new terminal window, log into server0 and start the xftp_basic_server.

     ssh server0
     cd /xia-core/applications/example
     ./xftp_basic_server
     

   • Open a new terminal window, log into host0 and start the ftp_basic_client.

     ssh host0
     cd /xia-core/applications/example
     ./xftp_basic_client
     

   • Transfer a file.
     

     get sample.txt sample.txt.1
     

   • Close tcpdump on router1

     C-c
     

     Note how CID requests have gone through router1 to reach server0 by looking at the number of packets transmitted.
8. See the effects of opportunistic caching.
   When the content (CIDs) were being transferred through the network, routers opportunistically cached them. Now when future requests for these CIDs are sent, the fallback to server0 does not need to be used, and the requests can be satisfied by the network itself. This means that there should be much less traffic on the link between router1 and server0, verified using tcpdump.
   • First, verify that the network (e.g., router1) has opportunistically cached this content.

     bin/xroute
     

     Note the many CIDs with "self" routes indicating the content is cached in router1
   • Relaunch tcpdump on router1

     sudo tcpdump -i `ifconfig | awk '/10.10.3.1/ {print $1}' RS="\n\n"` "not ether dst ff:ff:ff:ff:ff:ff"
     

   • Transfer the file again on host0.

     get sample.txt sample.txt.2
     

   • Close tcpdump on router1

     C-c
     

     Note how CID requests have not gone through router1 to reach server0 by looking at the number of packets transmitted.
   • Close xftp on server0

     C-c
     

   • Close xftp on host0

     C-c
     

Tutorial Part 2B: Add the new principal type