EE450-U7-DataLinkLayer-Nazarian-Summer11

EE450-U7-DataLinkLayer-Nazarian-Summer11 - University of...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: University of Southern California University of Southern California Viterbi School of Engineering Viterbi School of Engineering EE450 omputer Networks Computer Networks ata Link Layer Data Link Layer Shahin Nazarian Summer 2011 Data Link Layer (DLL) a Link to Link Protocol Every layer provides a set of services and provides it to the layer it _____ it DLL (Layer 2) is a link-to-link basis (not end-to-end basis) protocol Receiver side needs to synch frame (to know where it starts where it nds ) ceiver the other side of ends.) Receiver is the other side of the link Physical layer transmits the bit and makes sure no duplicate or missing bit exists, but DLL handles the errors (caused by noise or signal Shahin Nazarian/EE450/Summer 2011 attenuation) 2 Where Is The Link Layer (LL) Implemented? LL is implemented in each and every node uch of LL controllers functionality Example: host link layer Much of LL controller s functionality is implemented in hardware LL is implemented in adaptor (aka r host schematic application transport Network Interface Card or ____ card) E.g., Ethernet card (Intels 254x controller) PCM IA cpu memory host us network link 8254x controller), PCM-CIA card (plug-in to PCs PCI card slot), 802.11 card (Atheros R5006) controller physical transmission bus (e.g., PCI) link physical AR5006) Implements ___, Physical layer Attaches into nodes system buses network adapter card (aka network Interface card) Shahin Nazarian/EE450/Summer 2011 LL is a combination of hardware, software, and firmware 3 Some DLL Services 1. 1. Framing Framing Frame _____________ , adding header and trailer and ncapsulating acket into frame encapsulating packet into frame 2. 2. Error Error detection detection, done by the receiver node, using parity checks, FCS FCS ( Frame ______ _______ Frame ______ _______ ,) etc. rr r c ntr l rr r c ntr l ne by receiver n de usin ne f the f ll win 3. 3. Error control, Error control, done by receiver node, using one of the following (note that the transport layer _____________ error correction) Drop the Frame Receiver simply drops the frame _____ _____ ( Automatic Repeat Automatic Repeat reQuest reQuest ) protocols rror correction Error correction 4. 4. Flow Flow control control (to prevent buffer overflow at the receiver, i.e., to ensure the receiver is not ___________ by the sender) Shahin Nazarian/EE450/Summer 2011 Stop & Wait Sliding Sliding _______ Protocol _______ Protocol 4 Error Control, Flow Control Error Control Error Control 1 st technique [simplest approach]: In case error is etected receiver will drop the frame so automatically detected, receiver will drop the frame. so automatically packet is dropped as well 2 nd technique: Receiver will request from the sender (Note: not the end node, but the node on the other side of the link) to retransmit using ARQ rd chnique Receiver is not only able to detect the 3 technique: Receiver is not only able to detect the...
View Full Document

Page1 / 156

EE450-U7-DataLinkLayer-Nazarian-Summer11 - University of...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online