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Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X6148-GE-TX Modules used in a Server Farm

I am running those modules in my Cisco 6500 chassis and having lot of connectivity issues.  I lose network connectivity every 5-6 day at around the same time.  I have (2) C7000 Chassis with HP VC-Flex 10 Modules connected via 20Gb LAB to each Cisco Cisco 6513 Switches.  However, the OA Modules on C7000 are connected via 1Gb uplink to either 6548 and 6148 modules.  I beleive this is causing the netwok connectivity issues.

What modules would be recommended to replace 6548 and 6148 who only meant to be used for 1Gb desktop connectivity, and not for Server Farm.

See below this directly from Cisco:

When you use either the WS-X6548-GE-TX or WS-X6148-GE-TX modules, there is a possibility that individual port utilization can lead to connectivity problems or packet loss on the surrounding interfaces. Especially when you use EtherChannel and Remote Switched Port Analyzer (RSPAN) in these line cards, you can potentially see the slow response due to packet loss. These line cards are oversubscription cards that are designed to extend gigabit to the desktop and might not be ideal for server farm connectivity. On these modules there is a single 1-Gigabit Ethernet uplink from the port ASIC that supports eight ports. These cards share a 1 Mb buffer between a group of ports (1-8, 9-16, 17-24, 25-32, 33-40, and 41-48) since each block of eight ports is 8:1 oversubscribed. The aggregate throughput of each block of eight ports cannot exceed 1 Gbps. Table 4 in the Cisco Catalyst 6500 Series 10/100- & 10/100/1000-Mbps Ethernet Interface Modules shows the different types of Ethernet interface modules and the supported buffer size per port.

Oversubscription happens due to multiple ports combined into a single Pinnacle ASIC. The Pinnacle ASIC is a direct memory access (DMA) engine that transfers packets between backplane switching bus and the network ports. If any port in this range receives or transmits traffic at a rate that exceeds its bandwidth or utilizes a large amount of buffers to handle bursts of traffic, the other ports in the same range can potentially experience packet loss. The buffer assignment on these modules is documented in Buffers, Queues & Thresholds on Catalyst 6500 Ethernet Modules.

A SPAN destination is a very common cause since it is not uncommon to copy traffic from an entire VLAN or multiple ports to a single interface. On a card with individual interface buffers, the packets that exceed the bandwidth of the destination port are silently dropped and no other ports are affected. With a shared buffer, this causes connectivity problems for the other ports on this range. In most scenarios, shared buffers do not result in any problems. Even with eight gigabit attached workstations, it is rare that the provided bandwidth is exceeded.

The switch can experience degradation in services when you configure local SPAN in a switch, especially if it monitors a large amount of source ports. This problem remains if it monitors certain VLANs and if a large number or ports is assigned to any of these VLANs.

Even though SPAN is done in hardware, there is a performance impact since now the switch carries twice as much traffic. Since each linecard replicates the traffic at ingress, whenever a port is monitored, all ingress traffic is doubled when it hits the fabric. The capture of traffic from a large number of busy ports on a linecard can fill up the fabric connection, especially with the WS-6548-GE-TX cards, which only have an 8 Gigabit fabric connection.

The WS-X6548-GE-TX, WS-X6548V-GE-TX, WS-X6148-GE-TX, and WS-X6148V-GE-TX modules have a limitation with EtherChannel. For EtherChannel, the data from all links in a bundle goes to the port ASIC, even though the data is destined for another link. This data consumes bandwidth in the 1-Gigabit Ethernet link. For these modules, the sum total of all data on an EtherChannel cannot exceed 1 Gigabit.

3 ACCEPTED SOLUTIONS

Accepted Solutions
Super Bronze

Re: Connectivity Problem or Packet Loss with WS-X6548-GE-TX and

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

6724 or 6748 (with DFC).  (NB: with a 6513 and sup720, only 5 botom slots offer 40 Gbps)

Hall of Fame Super Gold

Re: Connectivity Problem or Packet Loss with WS-X6548-GE-TX and

Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X6148-GE-TX Modules used in a Server Farm

This subject line alone comes to no surprise and one would expect when you stick an ACCESS switch-level line card and connect SERVERS.  Both the 6148 and the 6548 weren't design for the server environment.  This responsibility falls squarely on the 6748 (hence you won't find a PoE version of this card).

Hall of Fame Super Gold

Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X

Before you go out and buy one, just want to make sure that the client has no intention of upgrading to Sup2T.  If the client has NO intention then go ahead and recommend the 6748 line card for the server farm.  If they do have the intention to upgrade to the Sup2T, then just be warned that the 6748 will not be supported by the Sup2T until you upgrade the DFC/PFC card.

5 REPLIES
Super Bronze

Re: Connectivity Problem or Packet Loss with WS-X6548-GE-TX and

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

6724 or 6748 (with DFC).  (NB: with a 6513 and sup720, only 5 botom slots offer 40 Gbps)

Hall of Fame Super Gold

Re: Connectivity Problem or Packet Loss with WS-X6548-GE-TX and

Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X6148-GE-TX Modules used in a Server Farm

This subject line alone comes to no surprise and one would expect when you stick an ACCESS switch-level line card and connect SERVERS.  Both the 6148 and the 6548 weren't design for the server environment.  This responsibility falls squarely on the 6748 (hence you won't find a PoE version of this card).

New Member

Re: Connectivity Problem or Packet Loss with WS-X6548-GE-TX and

Thanks!  This is one of our customers and am helping with new module.  Thanks for the information.  I did look up on CCO and exactly 6748 would be an optimal choice..

Thanks

Hall of Fame Super Gold

Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X

Before you go out and buy one, just want to make sure that the client has no intention of upgrading to Sup2T.  If the client has NO intention then go ahead and recommend the 6748 line card for the server farm.  If they do have the intention to upgrade to the Sup2T, then just be warned that the 6748 will not be supported by the Sup2T until you upgrade the DFC/PFC card.

Hall of Fame Super Gold

Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X

Thanks for the ratings.

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