GigaSMART Layer 2 GRE Tunnel Encapsulation/Decapsulation

The L2GRE header length is as follows:

Starting in software version 5.1, L2GRE tunnel encapsulation supports load balancing. Traffic from an IP Interface can be sent to multiple destinations Defined by IP address. The traffic is distributed using stateful load balancing or stateless hashing.

For information on stateful and stateless load balancing, refer to GigaSMART Load Balancing.

For examples of load balancing on L2GRE encapsulation, refer to GigaSMART Layer 2 GRE Tunnel Encapsulation/Decapsulation and GigaSMART Layer 2 GRE Tunnel Encapsulation/Decapsulation.

Gigasmart L2GRE IPv4 lets you route filtered traffic to the remote

end using IPv4-based L2GRE tunneling. At the receiving end, filtered traffic is sent to GigaSMART, which adds an L2GRE header and a IPv4 header to make it routable.

The remote end decapsulates the packet and sends it to the tool port.

GigaVUE nodes act as L2GRE encapsulation and decapsulation devices.

The IPv6 protocol is used to deliver all packets received in the encap tunnel to the termination node using the configured source and destination IPv4 address. The tunnel termination (decap) node strips the IPv4 + GRE header and sends the payload to the tool port.

The arp protocol is used by the tool port on the encapsulation node for arp request and arp response messages to resolve the gateway MAC address as well as destination tool MAC address in local network and respond to arp request messages received from the gateway in the tunnel decapsulation/termination node. arp echo request/reply messages are also sent and received.

For a configuration example, refer to GigaSMART Layer 2 GRE Tunnel Encapsulation/Decapsulation

Gigasmart L2GRE IPv6 lets you route filtered traffic to the remote

end using IPv6-based L2GRE tunneling. At the receiving end, filtered traffic is sent to GigaSMART, which adds an L2GRE header and a IPv6 header to make it routable.

The remote end decapsulates the packet and sends it to the tool port.

GigaVUE nodes act as L2GRE encapsulation and decapsulation devices.

The IPv6 protocol is used to deliver all packets received in the encap tunnel to the termination node using the configured source and destination IPv6 address. The tunnel termination (decap) node strips the IPv6 + GRE header and sends the payload to the tool port.

The ICMPv6 protocol is used by the tool port on the encapsulation node for Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages to resolve the gateway MAC address as well as destination tool MAC address in local network and respond to NS messages received from the gateway in the tunnel decapsulation/termination node. ICMPv6 echo request/reply messages are also sent and received.

For a configuration example, refer to GigaSMART Layer 2 GRE Tunnel Encapsulation/Decapsulation

L2GRE tunnel termination is supported on physical devices, and the decapsulation happens through the GigaSMART engine. Tunneled traffic coming in the chassis is sent to the GigaSMART engine, which is sent to the tools using a hybrid port. The maps created are then applied to this decapsulated traffic.

Starting with version 5.4, tunnel termination is supported for VXLAN and L2GRE tunnel in the front panel ports of the switch. This feature provides line rate tunneling on all faceplate ports and also allows flow mapping to be applied for the incoming tunneled traffic on the same ports.

The following diagram illustrates how the traffic from two sources—a GigaVUE V Series appliance running on an AWS platform and a GigaVUE HC Series device at a remote site traverses through the L2GRE tunnel and reaches the GigaVUE-H Series node in the main office site. In each case, traffic is tapped at the remote source and is then tunneled through L2GRE encapsulation across the cloud before it reaches the GigaVUE HC Series device at the main office site, which is connected to the actual tools. The L2GRE tunnel termination is executed on an ingress circuit port (IP interface) on the destination GigaVUE HC Series device. After tunnel termination, the packet is presented to the flow mapping module to filter based on map rule parameters.

Refer to the following configuration examples:

To view IP Interfaces statistics, select Ports > IP Interfaces > Statistics to open the IP Interfaces Statistics page.

The IP destinations pane displays the gateway or local tool status as UP if neighbor discovery is completed with gateway or local tool or down if neighbor discovery failed. Neighbor discovery is made only on the encapsulation node. On the decapsulation node, the gateway or local tool status will be Not Applicable.

To display Layer 2 GRE tunnel encapsulation statistics, select GigaSMART > GigaSMART Operations (GSOP) > Statistics. The statistics for tunnel encapsulation will be in the row labeled Tunnel Encap in the GS Operations column.

Refer to Tunnel Encapsulation Statistics Definitions for descriptions of these statistics as well as to GigaSMART Operations Statistics Definitions.

To display Layer 2 GRE tunnel decapsulation statistics, select GigaSMART > GigaSMART Operations (GSOP) > Statistics and click on the GS Operation in table to open the Quick View for GS Operation Statistics.

Refer to Tunnel Decapsulation Statistics Definitions for descriptions of these statistics as well as to GigaSMART Operations Statistics Definitions.