SMDS
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| The five layer TCP/IP model |
| 5. Application layer |
|
DHCP • DNS • FTP • HTTP • IMAP4 • IRC • NNTP • XMPP • MIME • POP3 • SIP • SMTP • SNMP • SSH • TELNET • BGP • RPC • RTP • RTCP • TLS/SSL • SDP • SOAP • L2TP • PPTP • … |
| 4. Transport layer |
| 3. Network layer |
| 2. Data link layer |
|
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| 1. Physical layer |
|
Ethernet physical layer • ISDN • Modems • PLC • SONET/SDH • G.709 • Wi-Fi • … |
SMDS, which stands for Switched Multi-megabit Data Services, was a connectionless service used to connect LANs, MANs and WANs to exchange data. SMDS was based on the IEEE 802.6 DQDB standard. SMDS fragmented its datagrams into smaller "cells" for transport, and can be viewed as a technological precursor of ATM.
Increases in raw data rates removed the need for fragmentation into cells, and SMDS' niche market position ensured that it remained a high-priced service. As a result, SMDS has been supplanted by IP-based and Ethernet-based services and MPLS.
