Bridge operate on data link layer
Data Link Layer
Layer 2 - Data Link
TELNET
The most common WAN data-link protocols are: 1. HDLC 2. PPP 3. Frame Relay 4. ATM
No. A digital subscriber line (DSL) operates at layer 2 or the Data-link layer.
physical layer.
data link
The Network Interface cards
Hubs are a physical layer (layer 1) device; most switches operate at the Data Link layer (Layer 2) of the OSI model.
Here's what you should know: Data link layer protocols must be concerned with the rules for transmitting data across the network media, particularly with encoding and carrying "frames" of data. Although this layer includes providing error detection and notification by adding the Cyclic Redundancy Check (CRC), the Transport Layer is primarily responsible for end-to-end error-free message delivery. WAN Data-Link protocols primarily define how data frames should be packaged for different types of networks. To quote: The data link protocols available for WAN communications define how networks will carry the data frames on a given data link. The data link protocols used for WANs come in three categories: 1. Interface to IBM enterprise data centers: SDLC 2. WAN connections using peer devices: HDLC & PPP 3. Switched or relayed services: X.25/LAPB, Frame Relay, ISDN/LAPD, ATM. Some of these protocols provide functionality as high as in the Network layer of the OSI, and all of these protocols transfer data over a WAN data link.
The role is to transfer frames to packets