In a layer II network three UAs are connected to a S3528G. S3528G is connected with one trunk link to one NE20 router. The NE20 is connected to a NE40 router trough E1s and VPLS configuration. NE40 router is connected to A-Corp Metro Ethernet device with two GigaEthernet interfaces configured with Eth-trunk. After several troubleshooting applied on all network devices and confirming that UA and connections, S3528G and connections, and VPLS connection were OK, what was the reason of the failure of one of three UAs connected to the same Datacom devices?
Since the beginning only one GigaEthernet interface of NE40 router connected to Metro Ethernet device was activated. We exchanged between them and the problem persisted. When we activated both at the same time the rest of UAs service were also affected. Customer confirmed that link-aggregation wasn’t configured on Metro Ethernet device and they couldn’t activate it at that time. In the NE40 router we removed the Eth-trunk configuration and we configured all VLANs in the activated GigaEthernet interface. After that service was OK in all UAs. Some link-aggregation negotiation in the activated interface was failing because the missing configuration on Metro Ethernet and the MAC address of that UA wasn’t being transfer between Metro Ethernet and NE40 router.
Be aware of link-aggregation configuration between different devices