| Title: | FDDI - The Next Generation |
| Moderator: | NETCAD::STEFANI |
| Created: | Thu Apr 27 1989 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2259 |
| Total number of notes: | 8590 |
Hi There,
My name is Laurie Richards and I'm a specialist at a customer site where we
will soon be implementing FDDI. We have a multi-lobed MIVC and plan to use
FDDI between CI hubs. Our main concern is that our FDDI solution uses Cisco
routers with encapsulating bridges and therefore the 6000s can use FDDI
to talk to each other, but must use their Ethernet interface to talk to
Ethernet nodes. Below is our proposed cluster configuration followed by some
questions and concerns. We would appreciate your answers, comments,
additional concerns, or questions regarding our planned configuration. Cisco
is expected to have translating bridges by March 1992, but our current high
Ethernet utilization (average 45-50%; peak 75-85%) requires us to go forward
with the FDDI implementation immediately. I've also submitted this note
to the clusters note conference. Thanks in advance for all your help.
Thanks,
Laurie Richards & Rob Clark
Proposed Cluster Configuration Using FDDI:
------------------------------------------
Our customer has purchased 5 DECconcentrator 500s and 6 Cisco AGS+ FDDI
Routers with bridging software to build an FDDI backbone network. FDDI
controller 400s (DEMFAs) have been purchased for the 6000s. Each of the
Cisco routers will be configured to support 6 Ethernets and a single FDDI
backbone. The plan is to leave all of the VAXes in their current locations
and to connect the 6000s to their own Ethernet (via the Cisco) and to the
FDDI backbone (via the DECconcentrators). The hope is that the 6000s will
use the FDDI backbone to communicate directly with each other and will use
their Ethernet interface when talking to other Ethernet nodes. Ethernet
traffic destined for nodes located on Ethernets attached to other Cisco
routers on the FDDI ring will travel accross the FDDI backbone. The
following is a simplified diagram of our proposed configuration:
6000 8650 8650 8650 8650
| | | | | |
____| |____ | | | |
| | | | | | BUILDING 618
FDDI E T H E R N E T |
CONCEN. C I S C O R O U T E R
| FDDI DAS
| |
+====================================+
| |
| FDDI BACKBONE NETWORK |
| |
+====================================+
| |
| FDDI DAS
FDDI C I S C O R O U T E R
CONCEN. E T H E R N E T BUILDING 355
| | |
---- ---- |
| | |
6000 8550
Questions/Concerns:
-------------------
1. Will the above configuration work? In short, will the 6000s know to use
their Ethernet interface to communicate with Ethernet nodes and use their FDDI
interface to communicate with each other?
2. How do the 6000s determine which interface to use when communicating with
other nodes?
3. With volume shadowing can the 6000 be designated to ensure that all volume
shadowing traffic goes over the FDDI and not the Ethernet.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 409.1 | KONING::KONING | Paul Koning, NI1D | Thu Dec 05 1991 11:22 | 17 | |
I'll leave it to the cluster wizards to answer your questions, but I'll add a few more... At first glance this configuration looks workable. But I wonder if the cisco boxes, acting as bridges, will have adequate capacity. I understand they are pretty fast routers, but fast routers aren't necessarily adequately fast bridges. As an alternative, you might consider putting DECbridges (5xx or more likely 6xx series) in parallel with the routers. Then the routers can stick to routing, and the bridges can handle the other traffic. This would require careful filtering setup. As yet another alternative you might avoid the cisco boxes and go for just bridging. paul | |||||
| 409.2 | Clusters and FDDI/Ethernet | CVG::LEKAS | From the Workstation of Tony Lekas | Fri Dec 06 1991 05:18 | 11 |
Since the VAX 6000s will only be able to see the Ethernet only connected nodes through their Ethernet adapters the VAX 6000s will communicate with them through the Ethernet adapters. In general, If there is only one path between nodes the cluster software will use that path. If there is both an FDDI and a Ethernet path FDDI will be used. If there are multiple FDDI paths, or if there is no FDDI and there are multiple Ethernet path the path with the lowest latency will be used. Tony | |||||