FDDI Translation Bridging
To ensure multivendor interoperability, the bridge protocol should be based
on the IEEE 802.1 Spanning Tree Protocol. Translation is required when
bridging between LANs with different data-link-layer characteristics. For
example, forwarding from an Ethernet to an 802.3 end station requires a
translation. When bridging Ethernet or 802.3 packets to FDDI media, a
MAC-layer translation is also required.
The 802.1 standards define how a received packet is formatted for transfer
across an intervening LAN (802.x or FDDI) and presented to a destination
LAN. In general, Ethernet Version 2 frames are encapsulated according to
rules specified in RFC 1042, and then converted back to Ethernet format.
IEEE 802.3/802.2 LLC and 802.3/LLC+SNAP remain unchanged when trans-
ferred across an intervening LAN. Table 1 summarizes translation rules.
Table 2 summarizes protocol-specific translation.
Table 1. Translation Rules for Encapsulation
Source Network
Encapsulation
Translation Rules
Destination Network
Encapsulation
Ethernet
RFC 1042
(SNAP OUI 00-00-00)
Ethernet
802.3/LLC + SNAP
FDDI LLC + SNAP
802.3/LLC + SNAP
802.3/802.2 LLC
FDDI 802.2 LLC
802.3/802.2 LLC
Table 2. Protocol Translation and Encapsulation
Protocol
Source Type
Translation Rules
Destination Type
XNS
Ethernet
RFC 1042
Ethernet
DECnet Phase IV
Ethernet
RFC 1042
Ethernet
Novell
Proprietary
RFC 1042
Ethernet
Novell
Ethernet
RFC 1042
Ethernet
AppleTalk Phase 2
LLC+SNAP
LLC + SNAP
LLC + SNAP
Source Routing
802.2 LLC
802.2 LLC
802.2 LLC
IP
Ethernet
RFC 1042
Ethernet
IP
LLC+SNAP
LLC + SNAP
LLC + SNAP
Shining a Light on FDDI
Internetworking with HP Routers
3-54
Summary of Contents for 600 Series
Page 1: ...Hewlett Packard Series 200 400 and 600 Routers HP Routing Services and Applications ...
Page 4: ......
Page 5: ...1 Product Notes ...
Page 6: ...Features of HP Routers Architecture and Technology Branch Office Routing Product Notes 1 2 ...
Page 38: ...Architecture and Technology Software Control Path Architecture 1 34 ...
Page 52: ...Branch Office Routing Future Directions 1 48 ...
Page 53: ...2 Routing Services Notes ...
Page 106: ...Bridging Service Traffic Prioritization 2 54 ...
Page 158: ...Novell IPX Routing Service NetBIOS Protocol Support 2 106 ...
Page 194: ...Data Compression for WAN Links Conclusion 2 142 ...
Page 195: ...3 Application Notes and Case Studies ...
Page 224: ...Improving Network Availability Application Recovery 3 30 ...
Page 234: ...ISDN Wide Area Network Design Dry Creek Joint Elem School District Performance 3 40 ...
Page 316: ......