Telecom Routers Switches Interview Preparation Guide
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Telecom Routers Switches frequently Asked Questions in various Telecom Switches Routers job Interviews by interviewer. The set of Telecom Routers Switches interview questions here ensures that you offer a perfect answer to the interview questions posed to you. Get preparation of Telecom Routers Switches job interview

18 Telecom Switches Routers Questions and Answers:

1 :: Which is a type of hub that forwards packets to an appropriate port based on the packets address?

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.

2 :: Most networks employ devices for routing services. Routers work at which OSI layers?

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

3 :: Which devices discriminates between multicast and unicast packets?

multicast packet deals with and routers

suppose a group of machines have the same ip address like 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

4 :: What is the Difference Between Routers, Switches and Hubs?

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.

5 :: Explain Bridging?

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.

6 :: What is the Difference between Router and Switch?

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.

7 :: What is causing Location Update(LU) delay when a roamer try to latch to a visited network?

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
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

8 :: Why is it that SMS/MO receives a sent and delivered acknowledgement but MT is not receiving the message?

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

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

9 :: Is a cross-over cable needed to connect the EZ serial switch to another hub or some type of device?

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

10 :: Does the EZ serial switch have a user configuration interface like a router?

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.

11 :: What is Auto-Negotiation function?

Auto-negotiation is a mechanism that takes control of the
cable when a connection is established to a network device.
Auto-negotiation detects the various modes that exist in
the device on the other end of the wire, and advertises it
own abilities to automatically configure the highest
performance mode of interoperation.
Auto-negotiation automatically switches to the correct
technology, such as 10BASE-T, 100BASE-TX, or a
corresponding Full Duplex mode. Once the highest
performance common mode is determined, Auto-negotiation
passes control of the cable to the appropriate technology
and becomes transparent until the connection is broken.

12 :: What is the IP address of the switch?

The switch can obtain its IP configuration automatically
using one of the following protocols:

?Bootstrap Protocol (BOOTP)

?Dynamic Host Configuration Protocol (DHCP)

?Reverse Address Resolution Protocol (RARP)

The switch makes BOOTP, DHCP, and RARP requests only if the
sc0 interface IP address is set to when the switch
boots up. This address is the default for a new switch or a
switch whose configuration file has been cleared using the
clear config all command. BOOTP, DHCP, and RARP requests
are only broadcast out the sc0 interface.

13 :: Will the switches work with both a PC/OS XP and a MAC/OS 9 if the uplink connection will be to a router?

Yes it will work.Its least bothered of pc/os it may be any
os.what it needs is MAC address of pcs.swithch is a
inteligent device which keeps ur pcs in one network to
communicate each other.

14 :: Does a switch have the ability to send IP addresses?

A switch takes the ip address and passes it through to the
other computer, whether that other computer has Dynamically
assigned it to its client or otherwise.

15 :: What are the differences between broadband router and Ethernet switch?

A switch, keeps a record of the MAC addresses of all the
devices connected to it. With this information, a switch
can identify which system is sitting on which port. So when
a frame is received, it knows exactly which port to send it
to, which significantly increases network response times.
And, unlike a Hub, a 10/100Mbps switch will allocate a full
10/100Mbps to each of its ports. So regardless of the
number of PCs transmitting, users will always have access
to the maximum amount of bandwidth. It's for these reasons
why a switch is considered to be a much better choice then
a hub.

Routers are completely different creatures. Where a hub or
switch is concerned with transmitting frames, a router's
job, as its name implies, is to route packets to other
networks until that packet ultimately reaches its
destination. One of the key features of a packet is that it
not only contains data, but the destination address of
where it's going.

A router is typically connected to at least two networks,
commonly two LANs or WANs or a LAN and its ISP's network
(ex. your pc or workgroup and EarthLink). Routers are
located at gateways, the places where two or more networks
connect. Using headers and forwarding tables, routers
determine the best path for forwarding the packets. Routers
use protocols such as ICMP to communicate with each other
and configure the best route between any two hosts.

A router will typically include a 4-to-8 port Ethernet
switch (or hub) and a Network Address Translator (NAT). In
addition, they usually include a Dynamic Host Configuration
Protocol (DHCP) server, Domain Name Service (DNS) proxy
server and a hardware firewall to protect the Local Area
Network (LAN) from malicious intrusion from the Internet.

16 :: What are the differences between an Ethernet switch and a hub?

In a hub, a frame is passed along or "broadcast" to every
one of its ports. It doesn't matter that the frame is only
destined for one port. The hub has no way of distinguishing
which port a frame should be sent to. Passing it along to
every port ensures that it will reach its intended
destination. This places a lot of traffic on the network
and can lead to poor network response times.

Additionally, a 10/100Mbps hub must share its bandwidth
with each and every one of its ports. So when only one PC
is broadcasting, it will have access to the maximum
available bandwidth. If, however, multiple PCs are
broadcasting, then that bandwidth will need to be divided
between all of those systems, which will degrade

A switch, on the other hand, keeps a record of the MAC
addresses of all the devices connected to it. With this
information, a switch can identify which system is sitting
on which port. So when a frame is received, it knows
exactly which port to send it to, which significantly
increases network response times. And, unlike a Hub, a
10/100Mbps switch will allocate a full 10/100Mbps to each
of its ports. So regardless of the number of PCs
transmitting, users will always have access to the maximum
amount of bandwidth. It's for these reasons

17 :: How to network the computers together with the switch?

Give each computer a static ip address in same range if just
connecting machines together.
With OS , the likes of server 2003, the server has fixed ip
and the clients obtain via DHCP their ip at the login to domain.