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Inter-network interface


In the telecommunications industry, a Network-to-Network Interface (Network-to-Network Interface, referred to as: NNI) is a specific designation of two networks The interface between signaling and management functions. An NNI circuit can be used for signaling (such as SS7), IP (such as MPLS), or ATM networks.

In MPLS or GMPLS-based networks, NNI is used for core provider routers (Provider Routers, category 4 or higher). In the case of GMPLS, the type of interconnection (interconnection) depends on the type of VRF (virtual routing and forwarding) exchange used for interconnection. It can be back-to-back, EBGP (external Border Gateway Protocol) or mixed NNI connection scenarios.

  • In the case of Back-to-Back, VRF is necessary to create VLANs (Virtual Local Area Network) and subsequent interfaces for NNI circuits The sub-interface (used for the VLAN message header and DLCI message header of Ethernet and Frame Relay network packets).

  • In the case of EBGPNNI interconnection, the P router (provider router) is told how to dynamically exchange VRF records without creating a VLAN. NNI is also used for the interconnection between two VoIP nodes.

  • In hybrid or full-mesh scenarios, there may be other types of NNI.

Asynchronous Transfer Mode

Asynchronous Transfer Mode (English: Asynchronous Transfer Mode, ATM), also known as the cell Following. ATM uses circuit switching, which uses cells as a unit. Each cell is 53 bytes long. The header occupies 5 bytes.

ATM can ideally realize a variety of QoS, and it can support connected services as well as connectionless services. It is a model of broadband ISDN (B-ISDN) technology. ATM is a switching technology. When sending data, the digital data is first cut into multiple fixed-length data packets, and then sent using optical fiber or DS1/DS3. After arriving at the destination, regroup. The ATM network can integrate sound, video and data at the same time. Provide the best transmission environment for various information types.

IEEE 802.1aq

IEEE 802.1aq (English: Shortest Path Bridging, abbreviated as SPB), is a computer network term . 802.1aq is a very important technology in increasing link bandwidth, realizing link transmission flexibility and engineering redundancy. 802.1aq is a logical upgrade of the Spanning Tree Protocol (Spanning Tree Protocol). 802.1aq includes the functions 802.1s, 802.1w, 802.1ax (link aggregation), MC-LAG, 802.1ak.


  • 802.1D (English: Spanning Tree, English: STP)

  • 802.1s (English: Multiple Spanning Trees, English: MSTP)

  • 802.1w (English: Rapid Reconfiguration of Spanning Tree, English: RSTP)

  • 802.1ak (English: Multiple MAC Registration Protocol, English: MMRP)

  • 802.1aq (English: Shortest Path Bridging, English: SPB)

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  • Mesh network

  • Spanning Tree Protocol

  • Link aggregation

  • Equal cost multipath routing

  • Software-defined network

  • Intermediate system to intermediate system

  • IEEE 802.1

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