Hello,
Today I would like to share with you the difference in the limitation of the number of VB attached VLANs created for EPLAN services when the EGS2 board is replaced with the EMS4 board.
Problem Description
There are more than 1,000 OSN 1500 sites on the existing network as MSAN transmission equipment, and each site is equipped with an N2EGS2 board to carry MSAN services. In order to cooperate with the MSAN site for protection, the two ports of EGS2 are required to protect each other. The configuration of the existing network is adopted The method is implemented as follows: Configure EPLAN service on EGS2, create a VB for EPLAN service, and connect VB to Port1 and Port2 and the corresponding VCTRUNK. When configuring VLANs in VB, many sites add VLAN IDs ranging from 1 to 4000.
Due to site expansion, a large number of customer sites need to replace EGS2 boards with EMS4 boards, reconfigure all services during the replacement process, and finally add the same ports (2 Ports and 1 VCTRUNK) when adding VLAN IDs after creating VB ) In this case, 4000 VLAN IDs cannot be added, resulting in unsuccessful board replacement.
Warning message
When adding a VLAN ID to the VB of the EMS4 board, it prompts that the number of VLANs exceeds the limit. For 2 port ports and 1 VCTRUNK port, only 2000 VLAN IDs can be added.
Process
1. Since the host supports 4k VLANs for the EGS2 board, the host problem can be ruled out. After consultation, it is determined that there is no such problem.
2. Query data and compare the indicators of EMS4 and EGS2 boards. Both have a limit of 4k on the number of VLANs.
3. Communicate with the access network about the VLAN ID actually used by the MSAN, and make sure that the actual VLAN ID used does not exceed 2000, generally only more than 60. On the next day, only more than 60 VLAN IDs actually used were added to the EMS4 board, and the board was replaced successfully.
Root cause
1. Host limit on the number of VLANs
2. The limitation of the single-board chip on the number of VLAN services
3. Single board software specifications limit the number of VLAN services
Conclusions
Due to the difference in the board software specifications, the number of VB-attached VLANs created by EMS4 and EGS2 for EPLAN services has the following similarities and differences.
1. Both the EGS2 board and the EMS4 board support the creation of 2 VBs, and both support 4000 VLANs, but there are certain differences when creating a VLAN filter table in the same VB.
2. When only 2 ports are connected to VB, EMS4 can add 4000 VLAN IDs just like EGS2.
3. When VB is connected to more than 2 ports, EGS2 also supports the addition of 4000 VLAN IDs, but EMS4 does not support the addition of 4000 VLAN IDs. The maximum number of VLANs is 4000/Nmax, and Nmax is the logical port in the VB connection port. Or the maximum number of physical ports. For example, if VB is connected to 2 Ports and 1 VCTRUNK, the maximum number of VLAN IDs is 2000, which is the situation we encountered; if VB is connected to 3 Ports and 1 VCTRUNK, the maximum number of VLAN IDs is It is 1333; if VB is connected to 1 port and 4 VCTRUNK, the maximum number of VLAN IDs is 1000, and so on.
4. In the configuration, we should follow the data set specifications. Like the situation we encountered, if the data set of EGS2 is set according to the actual situation at the beginning, it is not satisfied with 4000 VLAN IDs, the workload of this single board replacement will be greatly reduced.
You are welcome to leave a message and exchange in the comment area. Thank you!
