The Hello GPE World Tutorial

Introduction

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The SPP Components

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Pinging SPP External Interfaces

Unlike most PlanetLab nodes, an SPP has multiple external interfaces. In the GENI deployment, some of those interfaces have Internet2 IP addresses and some are interfaces attached to point-to-point links going directly to an external interfaces of other SPPs. This section introduces you to sone of the Internet2 interfaces.

Let's try to ping some of those Internet2 interfaces. Enter one of the following ping commands (omit the comments):

    ping -c 3 64.57.23.194         # Washington DC interface 0
    ping -c 3 64.57.23.198         # Washington DC interface 1
    ping -c 3 64.57.23.202         # Washington DC interface 2
    ping -c 3 64.57.23.210         # Salt Lake City interface 0
    ping -c 3 64.57.23.214         # Salt Lake City interface 1
    ping -c 3 64.57.23.218         # Salt Lake City interface 2
    ping -c 3 64.57.23.178         # Kansas City interface 0
    ping -c 3 64.57.23.182         # Kansas City interface 1
    ping -c 3 64.57.23.186         # Kansas City interface 2

For example, my output from the first ping command looks like this:

myhost> ping -c 3 64.57.23.194
PING 64.57.23.178 (64.57.23.178) 56(84) bytes of data.
64 bytes from 64.57.23.178: icmp_seq=1 ttl=56 time=67.5 ms
64 bytes from 64.57.23.178: icmp_seq=2 ttl=56 time=55.9 ms
64 bytes from 64.57.23.178: icmp_seq=3 ttl=56 time=59.0 ms

--- 64.57.23.178 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 55.949/60.823/67.511/4.895 ms

Note that you may not be able to ping an SPP external interface. Some reasons why you may fail are:

1. Your host doesn't have ping installed. This is not typical.
2. The SPP interface or the SPP is down.
3. Your network adminstrator blocks ping traffic.
4. Your network provider doesn't route Internet2 addresses.

In the first case, you will get a command not found error message. The ping command is usually located at /bin/ping. See your system administrator if you can't find ping. In the other cases, your ping command will eventually return with a 100% packet loss message. In the last case, running traceroute 64.57.23.178 may give a Network unreachable indication (the last router is marked !N).

If you are unsuccessful with one interface, try an interface of a different SPP.

However, you can always get around these problems (except for an SPP being down) if you can log into a PlanetLab node, and enter the ping command from there. We discuss how to log into a PlanetLab node in The IPv4 Metanet Tutorial.

Logging Into an SPP's GPE

Now, let's try to log into the Salt Lake City SPP (64.57.23.178). Note the following:

• You must use ssh to log into an SPP.
• When you ssh to an SPP's external interface, you will actually get logged into the GPE of the SPP.
• Furthermore, you will be logging into your slice in a GPE.
• Even if your network blocks your ping packets, you should be able to log into a GPE as long as there is a route to the SPP's external interface address.

If you have used ssh extensively, you probably know how to use an SSH agent so that you only enter your passphrase once. If so, you can skip over the next few paragraphs which are oriented for novice ssh users.

>>>>> HERE <<<<<

YOUR_SLICE XXXXX

    myhost> ssh -v -i ~/id_rsa YOUR_SLICE@64.57.23.210    # Salt Lake City

• The -v flag (verbose mode) causes ssh to output debug messages that indicate its progress.
• The argument following the -i flag indicates the private identity file.
• This form of ssh will prompt you for your passphrase.

If you are successful, you will get about 30 lines of debug output followed by a slice prompt that looks like this:

     myhost> ssh -v -i ~/id_rsa YOUR_SLICE@64.57.23.210
     debug1: Reading configuration data /etc/ssh/ssh_config
     debug1: Applying options for *
     debug1: Connecting to 64.57.23.210 [64.57.23.210] port 22.
     ... 20-30 lines of debug output ...
     Last login: Sun Feb 28 00:45:11 2010 from imbrium.seas.wustl.edu
     [YOUR_SLICE@salt_spp1 ~]$

Now, log out (enter exit or ctrl-d) and login again but omit the -v flag.

Experienced ssh users use ssh-agent or an equivalent utility (e.g., keychain, gnome-keyring-daemon) so that they only enter their passphrase once at the beginning of the day. Then, they login by enterring:

     myhost> ssh YOUR_SLICE@64.57.23.210

Furthermore, there is no prompt for a password or a passphrase. This approach substantially reduces a user's login effort, especially if he/she has to log into SPPs many times during the day.

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Getting Information About Interfaces and Peers

• The scfg utility
• scfg --cmd get_ifaces
• scfg --cmd get_peer

Constructing a Tunnel Map

• Use the output of get_ifaces and get_peer

Making a Resource Reservation

• scfg --cmd make_reservation and the reservation file
• Other reservation commands

Creating a Slowpath (GPE) Endpoint

• scfg --cmd alloc_plspec
• scfg --cmd alloc_endpoint