Table of Contents
- 1 Where does HOL blocking occur?
- 2 What is HOL blocking in a router?
- 3 What does each input port of a high speed router store to facilitate fast forwarding decisions?
- 4 How can packet loss occur at output ports?
- 5 Why does each input port in a high speed router store a shadow copy of the router’s forwarding table?
Where does HOL blocking occur?
Head-of-line (HoL) blocking occurs if there is a single queue of data packets waiting to be transmitted, and the packet at the head of the queue (line) cannot move forward due to congestion, even if other packets behind this one could.
What is HOL blocking in a router?
Head-of-line blocking (HOL blocking) in networking is a performance issue that occurs when a bunch of packets is blocked by the first packet in line. All packets received afterwards are not forwarded if the first one cannot be forwarded.
What is hol in networking?
Head-of-line blocking (HOL blocking) in computer networking is a performance-limiting phenomenon that occurs when a line of packets is held up by the first packet.
How can packet loss occur at input ports?
Answer: Packet loss occurs if the queue size at the input port grows large because of slow switching fabric speed and thus exhausting router’s buffer space. It can be eliminated if the switching fabric speed is at least n times as fast as the input line speed, where n is the number of input ports.
What does each input port of a high speed router store to facilitate fast forwarding decisions?
Forwarding is the process of sending the packet toward the destination based on the routing information. Discuss why each input port in a high-speed router stores a shadow copy of the forwarding table. Such decentralized forwarding avoids creating a forwarding processing bottleneck at a single point within the router.
How can packet loss occur at output ports?
Packet loss occurs if queue size at the input port grows large because of slow switching fabric speed and thus exhausting router’s buffer space. Packet loss can occur if the queue size at the output port grows large because of slow outgoing line-speed.
What is the HOL blocking issue in HTTP 1.1 how does HTTP 2 attempt to solve it?
HTTP Head of line blocking The head of line requests block the subsequent ones. HTTP/2 solves this by introducing multiplexing so that you can issue new requests over the same connection without having to wait for the previous ones to complete.
Does HTTP pipelining solve HOL blocking?
It is worth noting that HTTP/1.1 supports pipelining. But it really did not solve this kind of HOLB since a request that takes a lot of server processing time can still hold up subsequent responses. However, it’s layered on top of the same TCP protocol just like HTTP/1.1, so it cannot solve the TCP HOLB.
Why does each input port in a high speed router store a shadow copy of the router’s forwarding table?
Discuss why each input port in a high-speed router stores a shadow copy of the forwarding table. With the shadow copy, the forwarding decision is made locally, at each input port, without invoking the centralized routing processor. Describe how packet loss can occur at output ports.