Using MultiHop Analysis
Prerequisite: Observer Expert or Observer Suite
MultiHop Analysis is a powerful tool in Observer; it graphically shows you network conversations that traverse multiple network hops, making it easy to determine if delays are due to a particular router hop. For example, if you have a corporate LAN spread across remote offices, MultiHop Analysis can tell you which routers are causing network delay between remote offices and corporate headquarters.
If you ever encounter problems with MultiHop Analysis, see Troubleshooting synchronization errors or call the support team if you encounter issues specific to your network environment.
Tip! VIAVI included sample capture files so you can try MultiHop Analysis. These files are located in the \data subdirectory of wherever Observer was installed (C:\Program Files\Observer by default).
Before using the MultiHop Analysis tool, we recommend you become familiar with the user interface and creating packet captures from multiple probe instances—see Capturing from multiple probe instances for details.
Figure 37: MultiHop Analysis - the user interface
MultiHop Analysis user interfaceMultiHop Analysis user interface
Note: MultiHop Analysis only operates in post-capture mode; therefore, to make the tool work, you must absolutely save (or have saved) your capture files to disk and have access to those files.
To use MultiHop Analysis, complete the following steps:
1. Create and save multiple capture files—simultaneously—from multiple probe instances.
When capturing from multiple probe instances, there exists an option to immediately bring those captures into the MultiHop Analysis tool. For the sake of example, however, the proceeding steps ignore using that option.
2. On the Home tab, in the Analysis group, click MultiHop Analysis.
3. Click the Select Files to Analyze button. The MultiHop Analysis Settings window appears.
4. Ensure the Files tab is selected, and click the Add button. The Edit Segment File dialog appears.
Figure 38: The Edit Segment File dialog
Edit Segment Find dialogEdit Segment Find dialog
5. Type a descriptive name for your segment. In MultiHop Analysis, each capture file is called a segment.
6. Browse to or type the file location of the first capture file.
7. If you know or anticipate that IP addresses will not match between hops, enable the Apply IP Mapping option and click the Settings button.
IP mapping keeps track of network entities as they undergo network address translation. For more information about this option and its use, see How to use IP mapping in MultiHop Analysis.
8. Click OK to confirm this segment’s inclusion.
9. Repeat step 4 through step 8 for each capture file (segment) that you want to add to your MultiHop Analysis session. Up to ten segments can be added during this step; ten is the maximum.
10. Ensure you return to the MultiHop Analysis Settings window (which appeared in step 3), and click OK.
You successfully prepared the MultiHop Analysis tool and can now view and analyze the results.