Multihoming

Multi homing is a method to connect a single devide with more than one IP addresses to ensure reliability in the network.

Multihoming is a mechanism used to configure one computer with more than one network interface and multiple IP addresses. It provides enhanced and reliable Internet connectivity without compromising efficient performance. The multihoming computer is known as the host and is directly or indirectly connected to more than one network.


Point to remember:-

1.) Multihoming is intended to increase the reliability of network applications but it does not necessarily improve their performance. 
2.)

Stream Control Transmission Protocol

SCTP protocols is  transport layer protocol that is same as TCP or UDp, but supports the service features of both:
1.)message-oriented like UDP and
2.)in-sequence transport of messages with congestion control like TCP.


Features

Features of SCTP include:

    Multihoming support in which one or both endpoints of a connection can consist of more than one IP address, enabling transparent fail-over between redundant network paths.
    Delivery of chunks within independent streams eliminate unnecessary head-of-line blocking, as opposed to TCP byte-stream delivery.
    Path selection and monitoring select a primary data transmission path and test the connectivity of the transmission path.
    Validation and acknowledgment mechanisms protect against flooding attacks and provide notification of duplicated or missing data chunks.
    Improved error detection suitable for Ethernet jumbo frames.

The designers of SCTP originally intended it for the transport of telephony (Signaling System 7) over Internet Protocol, with the goal of duplicating some of the reliability attributes of the SS7 signaling network in IP. This IETF effort is known as SIGTRAN. In the meantime, other uses have been proposed, for example, the Diameter protocol and Reliable server pooling (RSerPool).

Intelligent Network Application Part (INAP)

Intelligent Network Application Part (INAP) is the signaling protocol used in Intelligent Networking.INAP is a signaling protocol between a service switching point (SSP), network media resources (intelligent peripherals), and a centralized network database called a service control point (SCP). The SCP consists of operator or 3rd party derived service logic programs and data.

Address Resolution Protocol (ARP)

Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP address) to a physical machine address that is recognized in the local network. For example, in IP Version 4, the most common level of IP in use today, an address is 32 bits long. In an Ethernet local area network, however, addresses for attached devices are 48 bits long. (The physical machine address is also known as a Media Access Control or MAC address.) A table, usually called the ARP cache, is used to maintain a correlation between each MAC address and its corresponding IP address. ARP provides the protocol rules for making this correlation and providing address conversion in both directions.
How ARP Works
When an incoming packet destined for a host machine on a particular local area network arrives at a gateway, the gateway asks the ARP program to find a physical host or MAC address that matches the IP address. The ARP program looks in the ARP cache and, if it finds the address, provides it so that the packet can be converted to the right packet length and format and sent to the machine. If no entry is found for the IP address, ARP broadcasts a request packet in a special format to all the machines on the LAN to see if one machine knows that it has that IP address associated with it. A machine that recognizes the IP address as its own returns a reply so indicating. ARP updates the ARP cache for future reference and then sends the packet to the MAC address that replied.

Since protocol details differ for each type of local area network, there are separate ARP Requests for Comments (RFC) for Ethernet, ATM, Fiber Distributed-Data Interface, HIPPI, and other protocols.

There is a Reverse ARP (RARP) for host machines that don't know their IP address. RARP enables them to request their IP address from the gateway's ARP cache.

Rehoming and resources sharing in network

A method, system, and apparatus enables automatic radio base station (RBS) rehoming from a first radio network controller (RNC) to a second RNC when the first RNC becomes overloaded and/or automatic resource sharing between/among RNCs when one RNC becomes overloaded. A managing/controlling entity receives load measuring reports from RNCs and analyzes them. If a first RNC is frequently and/or constantly experiencing an overcapacity condition, then an RBS of the RNC may be rehomed to a second RNC without operator intervention. If a first RNC temporarily experiences an overcapacity condition, then the workload of the first RNC may be shared by a second RNC also without operator intervention. When rehoming an RBS or sharing a load of a first RNC, ongoing connections are completed by the first RNC where the connection was initiated, but new connections are (for the rehoming case) or new connections may be (for load sharing cases) initiated using a second RNC.

TSC Transit Switching Center

 A number of products are available to build transit solutions:

The Transit Switching Center (also called TSC Classic) can be used to build hierarchical networks with centralized interconnect using TDM based technology.

In addition to the transit function, other optional functions can also be located in the Transit Switching Center, adding additional benefits and possibilities to create an optimized network solution:

The Gateway Mobile Switching Center (GMSC) for the interrogation of HLRService Switching Function (SSF) to interwork with an SCP nodeShort Message Service GMSC (SMS-GMSC), receiving all terminating Short Messages from the Short Message Service Centre 

Benefits

By introducing Transit Switching Centers, we can offer operators PLMNs that are easier and more cost effective to manage. Capacity can be released in the existing nodes, as the TSC is an integrated part of the PLMN.

Centralized interconnect to other PSTN/PLMNStructure large networks to interconnect regionsA more flexible network with reduced O&M costScalable capacity and comprehensive service capabilities maximize revenue potential