Understanding the network.pdf - Back to Home

Figure 1.15. IEEE enhancement to the OSI-RM.
All transport control protocols are considered Layer 2. Some of the more common
protocols are the following:
NOTE
• IEEE 802.X Ethernet, Fast Ethernet, Gigabit Ethernet. The most common
CSMA/CD baseband LAN protocol.
• ANSI X3T9.5 FDDI, Fiber Distributed Data Interface. A LAN/MAN redundant
transport technology that runs over fiber optic cable.
• ITU-T V.34 is the serial line standard used for modem transmissions up to
28.8Kbps.
• ITU-T V.90 is the serial line standard used for modem transmissions up to
53.3Kbps. This is the standard that replaced USR's X2 and Lucent/Rockwell's
Kflex proprietary standards.
Individuals who are just getting started with networking are often unfamiliar with
Layer 2 technologies. This is the result of Layer 2 and Layer 3 technologies being
commonly grouped together in discussions about topics (such as NT and UNIX
System Administration) that depend on networking, but are not primarily concerned
about its operation. The reality is that these two layers know nothing about what the
other is doing (and do not care). Their separation means that the ULP can leave
actual transport and data integrity to Layer 2. This partitioning of network delivery