| 84 | | The `install` and `execute` services requested in our RSpec have |
| 85 | | already started, and nodes in our experiment should be running the CCN (Content Centric Networking) protocol. Our experiment consists of: |
| 86 | | * A data source (node {{{dsrc1}}} that holds precipitation data from the US National Oceanic and Atmospheric Administration (NOAA). |
| 87 | | * A researcher node {{{rsrchr}}} that gets data from the data source |
| 88 | | * A collaborator node {{{collab}}} that gets data from the researcher |
| 89 | | |
| 90 | | Key features of the CCN protocol include: |
| 91 | | * Data is accessed by name. In our case we use a program called client to get precipitation data by date range (e.g. precipitation between 1902/01/01 and 1902/01/02). |
| 92 | | * All nodes cache data for a certain period of time. When a node receives a request for data, it checks its local cache. If the data is in it's cache, it returns that data. Otherwise, it forwards it on to its neighbor. |
| 93 | | |
| 94 | | We verify this caching behavior by: |
| 95 | | * Logging into the researcher node and using the client program to get precipitation data for a certain date range. The client displays how long it took to get the data. |
| 96 | | * Retrieving the same data again and noting how we get it much faster since it comes out of a cache. |
| 97 | | * Requesting data for different date ranges and seeing how long it took to retrieve the data. |
| 98 | | * Requesting the data again and note it is retrieved much faster. |
| 99 | | |
| 100 | | If you have time, you can repeat the above steps on the collaborator node. |
| 101 | | |
| 102 | | Note: There is an [wiki:GENIExperimenter/Tutorials/GettingStarted_PartII_ccn/Procedure/Execute/GEMINI optional part] to this exercise that uses the GENI Desktop to visualize traffic on the links in our network. There you can visualize which data requests went all the way to the data source (node {{{dsrc1}}}) and which data requests were fulfilled from a node's cache. |
| 103 | | |
| 104 | | === 5.1 Run the CCN application === |
| 105 | | 1. Log into the node {{{rsrchr}}} using the {{{ssh}}} command returned by {{{readyToLogin}}}. |
| 106 | | 2. Once you are logged in, ask for precipitation data from 1 Jan 1902 to 2 Jan 1902: |
| 107 | | {{{ |
| 108 | | $ /opt/ccnx-atmos/client.py |
| 109 | | Start Date in YYYY/MM/DD? 1902/01/01 |
| 110 | | End Date in YYYY/MM/DD? 1902/01/02 |
| 111 | | }}} |
| 112 | | 3. You should see output that looks like: |
| 113 | | {{{ |
| 114 | | Asking for /ndn/colostate.edu/netsec/pr_1902/01/01/00, Saving to pr_1902_01_01.tmp.nc |
| 115 | | Time for pr_1902_01_01.tmp.nc 1.09802699089= |
| 116 | | Asking for /ndn/colostate.edu/netsec/pr_1902/01/02/00, Saving to pr_1902_01_02.tmp.nc |
| 117 | | Time for pr_1902_01_02.tmp.nc 4.65998315811= |
| 118 | | Joining files.. |
| 119 | | Concat + write time 0.0735998153687 |
| 120 | | Wrote to pr_1902_1_1_1902_1_2.nc |
| 121 | | }}} |
| 122 | | Note that it took about 1.1 and 4.7 seconds respectively to retrieve data for Jan 1 and Jan 2 |
| 123 | | 4. Run the client again and request the same data. This time your output should look like: |
| 124 | | {{{ |
| 125 | | Asking for /ndn/colostate.edu/netsec/pr_1902/01/01/00, Saving to pr_1902_01_01.tmp.nc |
| 126 | | Time for pr_1902_01_01.tmp.nc 0.0423700809479= |
| 127 | | Asking for /ndn/colostate.edu/netsec/pr_1902/01/02/00, Saving to pr_1902_01_02.tmp.nc |
| 128 | | Time for pr_1902_01_02.tmp.nc 0.0388598442078= |
| 129 | | Joining files.. |
| 130 | | Concat + write time 0.0237510204315 |
| 131 | | Wrote to pr_1902_1_1_1902_1_2.nc |
| 132 | | }}} |
| 133 | | Notice how much faster the data was retrieved this time. |
| 134 | | 5. If time permits, log into the collaborator node {{{collab}}} and run queries from there. (Pick dates in January of 1902.) Notice different data retrieval times depending on whether the data came from the datasource, the cache at {{{rsrchr}}}, or the local cache. |
| | 92 | === 5.2 Run the NDN application on the entire topology === |
| | 93 | |
| | 94 | |
