NPB Network Packet Sniffer GTP GRE PPTP L2TP PPPOE Tunneling Protocol Label Header Stripping

Network Packet Broker GTP GRE PPTP L2TP PPPOE Tunneling Protocol Label Header Stripping
 
 Tunneling Protocol Identify Technology in Network Packet Broker
Supported automatically identify various tunneling protocols such as GTP / GRE / PPTP / L2TP / PPPOE. According to the user configuration, the traffic output strategy can be implemented according to the inner or outer layer of the tunnel
 
What is GRE Tunneling Protocol?
GRE(Generic Routing Encapsulation)can encapsulate Data packets of some network layer protocols (such as IPX, ATM, IPv6, AppleTalk, etc.)  so that these encapsulated data packets can be transmitted in another network layer protocol (such as IPv4).GRE provides a mechanism for encapsulating messages of one protocol in another. It is a three-layer tunneling technique that allows messages to be transmitted transparently through the GRE tunnel, solving the transmission problem of heterogeneous networks.
GRE implementation mechanism is simple, the tunnel at both ends of the equipment burden.The GRE tunnel can connect to the local network of various network protocols through the IPv4 network, effectively utilizing the original network architecture and reducing the cost.The GRE tunnel extends the scope of hop-limited network protocols to enable flexible enterprise network topologies.The GRE tunnel can encapsulate multicast data and ensure the security of voice, video and other multicast services when combined with IPSec.GRE tunnel support enables MPLS LDP. GRE tunnel is used to carry MPLS LDP messages, LDP LSP is established, and MPLS backbone network is interoperable.The GRE tunnel connects discrete subnets and is used to set up VPNS for secure connections between corporate headquarters and branches.
 
The protocol responsible for forwarding encapsulated packets is called the transport protocol.

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Network Packet Broker Tuneling Label stripping at GRE Application Scenarios 
4) Set up L2VPN and L3VPN through GRE tunnel
In general, MPLS VPN backbone networks usually use LSP as the public network tunnel.If the core device (P device) of the backbone does not have MPLS, and the edge device (PE device) does, then the backbone cannot use LSP as the public network tunnel.At this point, the backbone can use the GRE tunnel instead of the LSP to provide a layer 3 or 2 VPN solution on the backbone.
LDP over GRE technology enables MPLS LDP on the GRE tunnel interface, USES the GRE tunnel to carry MPLS LDP messages, and establishes LDP LSP.

As shown in the figure above, an enterprise deploying L2VPN or L3VPN services between PE1 and PE2 needs to establish a LDP LSP across the GRE tunnel between PE1 and PE2 due to the fact that the backbone equipment may not be enabled or support MPLS.

As shown in the figure above, a ldp-lsp across the GRE tunnel can be established by establishing a GRE tunnel between PE1 and P2 when MPLS is supported by the backbone P2 device, but not by the P1 device.
 
5) GRE tunnel was adopted for CE to access MPLS VPN
VPN service based on MPLS backbone network can provide better service than traditional IP VPN.Therefore, MPLS VPN technology is the mainstream VPN technology chosen by operators.But the Internet is based on IP technology, and the backbone network based on IP technology is still abundant.
In MPLS VPN, a direct physical link between CE (Customer Edge) and PE (Provider Edge) devices of MPLS backbone network is often required to connect the client device CE (Customer Edge) to the VPN, that is, in the same network.In such a network, the VPN needs to be associated with the PE to CE physical interface on the PE.
However, in the actual network, not all CE and PE can be directly connected by physical links.For example, many organizations that are already connected to the Internet or ip-based backbone networks are geographically far apart from their CE and PE devices, making direct access to MPLS backbone PE devices impossible.This prevents direct access to MPLS VPN sites from the Internet or the IP backbone.

To make CE accessible to MPLS VPN, consider creating a "logical direct connection" between CE and PE.That is, you can connect CE and PE using a public or private network and create a GRE tunnel between CE and PE.In this way, can be regarded as CE and PE directly connected.When you associate a VPN with the pe-ce interface on a PE, you can use the GRE tunnel as a physical interface on which to associate a VPN.
 
5.1 GRE through the public net
5.2 GRE for VPN traversal
5.3 GRE for private networks
What kind Network Packet Broker and Network Taps support Tunneling Protocol Identify Technology?

  
 
 
Network Packet Broker Specification and Module Type

NT-FTAP-32QCX Network TAP NPB.pdf