dditional PRC is needed. Most commonly, an operator conducting these tests is concerned with frequency wander in a net- work topology, unless there is some specific reason to be concerned about some other parameter (such as jitter) that is causing issues with the final application. Figure 12-14 shows the MTIE graph of the SyncE wander after crossing a (small) network of routers connected to an ePRTC with 10-GE links. Because the customer network uses option 1, and this is a network test, the appropriate mask to use when comparing the result is the G.8261 EEC Op- tion 1 wander limit. This capture comes from the Calnex Analysis Tool (CAT) post-processing a SyncE capture taken on a Calnex Sentinel field tester. The fact that the calculated MTIE stays well below the mask (on a logarithmic scale) means this is a very good result, which is as expected from a SyncE network. Wander Test Network TIE Date 2020-10 File channel1 dset 10000 2 000 1 000 G.8261 EEC Opt. 1 Wander Limit 1 TIE 10000 Observation Window (s) Figure 12-14 Example of a Network SyncE Wander Test This is the simplest but most practical use of testing frequency-trying to determine what the signal is doing at the end of the chain and whether it will meet your needs. That will answer questions such as whether it is good enough to synchronize the emulated TDM circuit, or provide a stable source for a radio transmitter. This test case makes sense where the clocks and transport system support SyncE. But if that support is not available, then the frequency must be carried using a packet-based approach. A test regime for that scenario is outlined in the following section. Testing Networks for Frequency Wander (Packet) There is one test case that is mentioned without too much detail, mainly because it is becoming in- creasingly less mainstream-the recovery of frequency using PTP rather than SyncE. Many mobile operators have been running the G.8265.1 telecom profile for frequency for quite some years, mainly to replace the TDM links that they used to syntonize the