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Configuration Guide - VPN

CloudEngine 12800 and 12800E V200R005C10

This document describes the configurations of VPN, including GRE, BGP/MPLS IP VPN, BGP/MPLS IPv6 VPN, VLL, PWE3, and VPLS.
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Licensing Requirements and Limitations for GRE

Licensing Requirements and Limitations for GRE

Involved Network Elements

Other network elements are not required.

License Requirements

GRE is a basic feature of a switch and is not under license control.

Version Requirements

Table 1-2 Products and minimum version supporting GRE

Product Model

Minimum Version Required





CE12800E (configured with FD-X series cards)


Feature Limitations

Limitations on GRE

  • The device supports a maximum of 2048 tunnel interfaces.
  • The device does not support multilayer GRE encapsulation or decapsulation.

  • The switch supports a maximum of ten source IP addresses for all IP tunnels.
  • CE devices do not support packet fragmentation and reassembly. If a packet encapsulated with a tunnel header exceeds the MTU of the outbound interface, the packet can be forwarded from a CE device without being fragmented. If the CE device functioning as the tunnel destination end receives a fragmented packet, the packet will be decapsulated incorrectly and then be discarded.
  • When an IP tunnel is encapsulated in a tunnel, the loopback is based on IP route forwarding of the external tunnel. The CE12800 uses an internal loopback interface on the chip. The forwarding performance is affected by the bandwidth of the internal loopback interface on the chip. For the CE12800, the total bandwidth for packets entering a GRE tunnel cannot exceed 100 Gbit/s per chip. This bandwidth limit does not apply to packets leaving the GRE tunnel.
  • To CE12800E (configured with FD-X series cards), the source interface of GRE tunnel cannot be layer 3 sub-interface.

Limitations on GRE traffic statistics

  • Starting from V100R005C00, the device supports only unicast GRE traffic statistics.
  • The device provides GRE or VPLS traffic statistics at one time.
  • Traffic statistics collection at the PW side and that on GRE tunnel interfaces cannot take effect simultaneously.
  • Some traffic statistics data will be lost after an active/standby switchover or a card restart.
  • If the same encapsulation IP addresses (same source and destination IP addresses) are configured for different IP tunnel interfaces, traffic statistics on the GRE tunnel interface are inaccurate.

  • Statistics about outgoing traffic (such as ping packets) generated by the CPU cannot be collected.

  • Traffic statistics collected on logical interfaces do not contain the bandwidth utilization.

Limitations when GRE is used with other services

  • Only the Admin-VS in port mode supports GRE; all VSs in group mode support GRE.
  • GRE tunnels consume internal forwarding resources of VLANs. Therefore, the number of VLANs that can be created on the device will decrease after GRE is configured. That is, less than 4063 VLANs can be created.
  • When the Keepalive function is enabled on a GRE tunnel, the GRE tunnel interface may frequently alternate between Up and Down due to insufficient ACLs. When configuring the Keepalive function, you need to configure control-flap to reduce the impact on device and network stability.
  • A GRE tunnel cannot be deployed between the UPE and NPE in HVPLS scenarios.
  • GRE and EVN conflict with each other and cannot be configured together.
Updated: 2019-04-03

Document ID: EDOC1100075353

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