Telecom Routers Switches Interview Preparation Guide

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Short for port-switching hub, a special type of hub that
forwards packets to the appropriate port based on the
packet's address. Conventional hubs simply rebroadcast
every packet to every port. Since switching hubs forward
each packet only to the required port, they provide much
better performance. Most switching hubs also support load
balancing, so that ports are dynamically reassigned to
different LAN segments based on traffic patterns.
Some newer switching hubs support both traditional Ethernet
(10 Mbps) and Fast Ethernet (100 Mbps) ports. This enables
the administrator to establish a dedicated, Fast Ethernet
channel for high-traffic devices such as servers.

Application layer
Presentation layer
Session layer
Transport layer
Network layer - Routers
Datalink layer - Switches
Physical layer - Hub

multicast packet deals with and routers

suppose a group of machines have the same ip address like 60.4.4.4 so router can send the packet to that network but here the every node will take care to deliver the packets to target (multiple routers) there is no need that grand parent(main sender) will take care of all family members wether they got the food(data packets) here the grand children (which is not directly with sender ) food(data packets) send by his children of grand parent(which is directly connected with the sender) so here router send the data to packets and all the nodes send the packets to the a physical address link up with that ip

unicast also deals with routers it will deals with one-to-one connection every parent have the direct relation with child

Routers connect different Networks .Routers can bring
different Networks together.

Switches bring different computers in Network together and
for fast use of Internet Access.The provided Bandwidth by
ISP is provided to all computers in network.

Hubs divide the Bandwidth provided by ISP and will provide
the slow Internet Access.

Bridging is a forwarding technique used in packet-switched computer networks. Unlike routing,
bridging makes no assumptions about where in a network a particular address is located. Instead,
it depends on flooding and examination of source addresses in received packet headers to locate
unknown devices. Once a device has been located, its location is recorded in a table where the
MAC address is stored so as to preclude the need for further broadcasting. The utility of bridging
is limited by its dependence on flooding, and is thus only used in local area networks.
Bridging generally refers to Transparent bridging or Learning bridge operation which
predominates in Ethernet. Another form of bridging, Source route bridging, was developed for
token ring networks.
A network bridge connects multiple network segments at the data link layer (Layer 2) of the OSI
model. In Ethernet networks, the term bridge formally means a device that behaves according to
the IEEE 802.1D standard. A bridge and switch are very much alike; a switch being a bridge with
numerous ports. Switch or Layer 2 switch is often used interchangeably with bridge.
Bridges are similar to repeaters or network hubs, devices that connect network segments at the
physical layer (Layer 1) of the OSI model; however, with bridging, traffic from one network is
managed rather than simply rebroadcast to adjacent network segments. Bridges are more
complex than hubs or repeaters. Bridges can analyze incoming data packets to determine if the
bridge is able to send the given packet to another segment of the network.

ROUTER interconnecting on layer 3, and SWITCH does it on layer 2.
ROUTER can access to different LANs, versus that the SWITCH can work only in the same LAN.
ROUTER changes the MAC addresses when pass from one LAN to another, versus that the
SWITCH can’t change it.
ROUTER do ―look‖ on the IP address, versus that the SWITCH don’t care form the IP address,
SWITCH ―look‖ on IP address as regular Data inside the frame.
ROUTER is defining the border of Broadcast Domain; versus that SWITCH define the border of
Collision Domain.

Due to various reasons for Lu problems:
1.Routing of GT mismatch at Visited network/visited MSC
2.IMSI analysis want to given properly in all the vis MSC's
3.Verify IMSI,IMSIINDICATOR,TON,NRD,SRD,SAD,DIA,PLMN NAME
4.No traffic is given current point code,where GT configured
5.HLR defintion at Home plmn country is wrong
6.HLR end not allowed given PLMN in roaming profile
7.HLR end GT mismatch
8.customer not having sufficient roaming services
9.customer not having authentication
10.customer handest's network id is disabled

MT stands for mobile terminated, which means the message
originated from mobileStorm and was ultimately sent
(terminated) at the end users cell phone. MO stands for
mobile originated, which means the end user created the
message or replied to a message via their cell phone.

Mobile-Terminated SMS (Short Message Service)

The capability for a mobile phone to receive short text
messages.

MT-SMS is usually accompanied by MO-SMS, which is the
ability to send and reply to such messages.

Cross Cabling is used to connect to similar devices in a
network.Here Cross-over cable is used to connect EZ Serial
Switch to Same type of device which is similar and not to
hub.

No, the EZ serial switch does not have a user configuration
interface because there is no need for a user to configure
an EZ serial switch to have a LAN/WAN based connection.
All the changes should be applied under the Operating
System itself.