1 / 10

MAC algorithm from the receiver side

MAC algorithm from the receiver side. Senders manage all access control Receivers merely read frames with acceptable address Addressed to host Broadcast address Addressed to multicast group to which host belongs All frames if host is in promiscuous mode. Fast Ethernet (100 Mbps).

triage
Download Presentation

MAC algorithm from the receiver side

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MAC algorithm from the receiver side • Senders manage all access control • Receivers merely read frames with acceptable address • Addressed to host • Broadcast address • Addressed to multicast group to which host belongs • All frames if host is in promiscuous mode

  2. Fast Ethernet (100 Mbps) • It has a technology which is very similar to 10 Mbps Ethernet • It uses a different physical layer encoding (4B5B) • Many NICs can support 10/100 Mbps • They may be used at both speeds

  3. Gigabit Ethernet (1000 Mbps) • It is compatible with lower speeds • It uses standard framing and CSMA/CD algorithm • Distances are very limited • It is typically used for backbones and inter-router connection

  4. Experiences with Ethernet • Ethernet networks work at best with light loads • Employment over 30% is considered to be heavy • network capability is wasted by collisions • Most networks are limited to about 200 hosts • Specification allows for up to 1024 • Most networks are much shorter • 5 to 10 microsecond RTT • Transport level flow control helps reduce load (number of back to back packets) • Ethernet is not expensive; it is fast and easy to administer

  5. Ethernet problems • Top usage is quite low (like Aloha) • Peak throughput is particularly low with: • More hosts • More collisions necessary to identify the single sender • Smaller packet sizes • More frequent arbitration • Longer links • It takes longer to notice collisions • Efficiency is improved by avoiding these conditions

  6. Reasons for Ethernet success • There are LOTS of LAN protocols • Price • Performance • Availability • Ease of use • Scalability

  7. Frame Ethernet revisited (1) • Preamble: 62 bit • SFD (Start of Frame Delimiter): 2 bit • Destination address: 6 byte • Source address: 6 byte • Length or frame type field: 2 byte • Data: from 46 to 1500 byte • FCS (Frame Check Sequence): 4 byte

  8. Frame Ethernet revisited (2) • Preamble: a sequence of alternating 1's and 0's used by the receiver to acquire bit-level synchronization • Start of Frame Delimiter: two consecutive 1 bits used to acquire byte alignment • Destination address: expected receiver address. Broadcast address is all 1s • Source address: unique address of the sender station

  9. FINE Frame Ethernet revisited (3) • Length or frame type: it is data byte number for IEEE 802.3 and the packet type for Ethernet I&II • Data: short packets must be padded up to 46 byte • Frame Check Sequence: it is a 32-bit cyclic redundancy check which is calculated using the AUTODIN II polynomial

More Related