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+16 votes

Match the following:
$$\begin{array}{llll} \text{(P)} & \text{SMTP} &(1)& \text{Application layer} \\ \text{(Q)} & \text{BGP}& (2) & \text{Transport layer} \\   \text{(R)} & \text{TCP}& (3) & \text{Data link layer} \\  \text{(S)} & \text{PPP}& (4) & \text{Network layer} \\ &&(5) & \text{Physical layer}  \\ \end{array}$$

  1. $\text{P - 2, Q - 1, R - 3, S - 5}$
  2. $\text{P - 1, Q - 4, R - 2, S - 3}$
  3. $\text{P - 1, Q - 4, R - 2, S - 5}$
  4. $\text{P - 2, Q - 4, R - 1, S - 3}$
in Computer Networks by Veteran (52.2k points)
edited by | 2.6k views

Answer: Option (B).

P - 1, Q - 4, R - 2 is Self Explanatory, but for S-PPP , refer:

In terms of the OSI model, PPP provides Layer 2, or data-link, service. PPP is a full-duplex protocol that can be used on a variety of physical media, including twisted pair copper wire, fiber optic lines or satellite links. PPP uses a variation of High-level Data Link Control (HDLC) for packet encapsulation.
if BGP is network layer protocol how does it use TCP as the transport layer?

4 Answers

+27 votes
Best answer

Answer is B.
SMTP is an application layer protocol used for e-mail transmission.
TCP is a core transport layer protocol.
BGP is a network layer protocol backing the core routing decisions on the Internet
PPP is a data link layer protocol commonly used in establishing a direct connection between two networking 

by Active (3.8k points)
edited by
BGP is a application layer protocol
BGP is n/w layer protocol,it is used to scale OSPF efficiently.

doubt : but Wikipedia says BGP is application layer protocol


BGP: It is a Network layer protocol.

Border Gateway Protocol (BGP) is a routing protocol used to transfer data and information between different host gateways, the Internet or autonomous systems. BGP is a Path Vector Protocol (PVP), which maintains paths to different hosts, networks and gateway routers and determines the routing decision based on that. It does not use Interior Gateway Protocol (IGP) metrics for routing decisions, but only decides the route based on path, network policies and rule sets.Sometimes, BGP is described as a reachability protocol rather than a routing protocol.

BGP roles include:

  • Because it is a PVP, BGP communicates the entire autonomous system/network path topology to other networks
  • Maintains its routing table with topologies of all externally connected networks
  • Supports classless interdomain routing (CIDR), which allocates Internet Protocol (IP) addresses to connected Internet devices

When used to facilitate communication between different autonomous systems, BGP is referred to as External BGP (EBGP). When used at host networks/autonomous systems, BGP is referred to as Internal BGP (IBGP).

+12 votes
I guess answer is (b) here.PPP is a data link layer protocol
by Active (2.4k points)
+7 votes
Correct answer is :: P - 1, Q - 4, R - 2, S - 3

SMTP is application layer protocol but take help of TCP for activation over link for transfering mail.

TCP:: It is transport layer protocol.

BGP:: Border Gateway procoly is used to connect two AS and used in Network layer.

While PPP:: Point to point connection with the help of MAC will come under the category of Data Link layer.
by Boss (10k points)
–5 votes
The answer is (C). PPP - refers to Point to Point Protocol which falls under Physical Layer.
by (17 points)

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