Table Of Contents
Release Notes for FDDI Version 1.19
May 11, 1998
These release notes describe the changes made to the FDDI module firmware between versions 1.14 and this version, 1.19. It also contains a log of the changes made to the FDDI module firmware since its initial release.
FDDI modules can be used with the Catalyst 2800, Catalyst 2820, EtherSwitch 1400, and EtherSwitch 1420 switches. The documentation for FDDI modules is as follows:
•Catalyst 2800 Modules User Guide
•Catalyst 2820 Modules User Guide
•EtherSwitch 1420 Modules Installation Guide
•EtherSwitch 1400 Modules User Guide
Upgrading FDDI Module Firmware with Xmodem
When performing an Xmodem upgrade of FDDI module firmware, set the Xmodem timeout value to 15 seconds or longer. Certain communications packages, such as Procomm Plus for Windows, version 1.01, set the Xmodem timeout value to less than 15 seconds; this could cause the timeout to fail.
This version resolves the problems described in the following sections.
Module Stops Forwarding from FDDI to Ethernet
After long periods of significant traffic flowing in the FDDI-to-Ethernet direction, the FDDI module can gradually loose buffers and stop forwarding this traffic. Traffic flowing in the Ethernet-to-FDDI direction is not affected.
A software fix has been implemented for this problem. Customers who notice this problem should upgrade to FDDI module software version 1.19. (CSCdj62826)
Module Does Not Forward Traffic Under Heavy Loads
Under certain conditions the FDDI module is unable to forward frames between FDDI and Ethernet. Version 1.19 is the first version to fix this problem. Customers who experience this problem should upgrade their module firmware to version 1.19. (CSCdj01039)
This version supports RFC 1191 Path MTU Discovery. When the FDDI module cannot forward an IP datagram because it exceeds the MTU of the next-hop (1500 bytes) and the Don't-Fragment bit is set, the FDDI module returns a Destination-Unreachable message to the datagram source. The message code is fragmentation needed and DF set. The Next-Hop MTU is set to 1500 in the ICMP header.
For this release, the source IP address is set to 0 in the ICMP message. This does not affect the operation of the MTU Discovery.
This release fixes the problems described in the following sections.
Loss of FDDI/Ethernet Connectivity
If an FDDI network has IP frames with an IP datagram larger than 1500 bytes and there is at least one error in the IP header or the Don't Fragment bit is set to drop oversized frames, the FDDI module might reset. FDDI/Ethernet connectivity is lost for about 15 seconds. This condition might also result in the loss of Ethernet/FDDI connectivity until the FDDI module is manually reset.
Loss of FDDI/Ethernet Connectivity for 15 Seconds
If an FDDI network has IP frames with the actual size of the FDDI frame larger than 1525 bytes (including FC and FCS) and the Total Length field in the IP header is equal to or less than 1500 bytes, the FDDI module resets. FDDI/Ethernet connectivity is lost for about 15 seconds.
Poor FDDI/Ethernet Performance
When the traffic on all the Ethernet ports is less than 10 packets per second, the switch might perform poorly after a few days. This light traffic causes a loss of FDDI/Ethernet connectivity or extremely poor FDDI/Ethernet performance. The switch needs to be rebooted to resume normal operation.
Elastic Buffer Error Counter Goes up During Reconfiguration
Elastic Buffer Error happens when a fiber-optic cable is connected to an inactive port on the FDDI module or when there is a reconfiguration. This is normal behavior. The Elastic Buffer Error counter should not increment because the port is inactive. The Elastic Buffer Error counter should only increment if the error occurs on an active port.
FDDI Module Disconnects Itself Permanently from FDDI Network after Beacon and Trace Conditions
When there is a Beacon or Trace condition on a FDDI network and the Requested Target Token Rotation Time of the FDDI module's upstream neighbor is better, the FDDI module detects a duplicate MAC address condition incorrectly and disconnects itself from the network. The FDDI module needs to be rebooted to resume normal operation.
Banyan Vines for Translational Bridging Not Supported
Banyan Vines requires a translational bridge to translate FDDI SNAP frames with 0x80C4 as the protocol type to an Ethernet II frame with 0x0BAD as the protocol type. The FDDI module does not perform the translation.
This release fixes the following problem.
When a source routing frame is received on FDDI, the FDDI module might reset itself or stop receiving user data frames from FDDI.
This release fixes the problems listed in the following sections.
IPX Communication Packets Between Two FDDI IPX Hosts Are Flooded to the Ethernet Ports
The FDDI module learns the source MAC address of an IPX frame only if the destination MAC address of the frame is unknown.
Assume there are two IPX stations with MAC addresses A and B on the FDDI network. When A sends a frame to B, the FDDI module learns source address A and forwards the frame to the Catalyst 2820 switch. The switch learns that address A is on the FDDI network. When B sends a frame to A, the FDDI module does not learn the address B, as the destination address A is known. As A is known to be on the FDDI network, the frame is dropped and not forwarded to the Catalyst 2820 switch.
When A sends a frame to B, the FDDI module does not know where B is and the frame is forwarded to the switch. As the switch does not know where B is, the frame is flooded to all the Ethernet ports.
All frames sent to B from A are flooded to all Ethernet ports.
The FDDI Module Causes a Network Management Station to See Incorrect FDDI Topology Map.
The FDDI module does not set the A (Address Recognized) and C (Copied) symbols in the frame status for frames that have a broadcast address (FF-FF-FF-FF-FF-FF) as their destination address.
This release fixes the following problem: FDDI module performance drops when a few thousand error-packets-per-second, intermixed with good frames, are forwarded from Ethernet ports to the FDDI network.
This release fixes the problems described in the following sections.
An Optical Bypass Is Not Detected
The FDDI module does not detect an optical bypass if it is inserted after the FDDI module becomes active.
IP Communication Between Ethernet and FDDI Hosts Might Not be Established
When an IP ARP packet is received from the FDDI network, the hardware type is not translated from 6 to 1 before the packet is forwarded to Ethernet. Some older IP implementations on Ethernet might not support the hardware type of 6 and drop the packet.
This release fixes the following problem: the FDDI module power-on self-test fails when the Catalyst 2820 receives more than 60 packets-per-second of broadcast packets.
This is the first release of the FDDI module.
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