Controller Based WLANs

Description about "show datapath port" command?

Question: Description about "show datapath port" command?

 

 

Product and Software: This article applies to all Product and Software

  • This table accessed when processing a frame. It contains PVID ACLs, MTU & Flags of the physical port
  • The port's flags are used to determine if the port is STP forwarding or blocking and if it is a TRUNK or a member of a LAG.

NOTE: Port are down will be on 'B' flag

  • Used to determine if the port is a Trunk for the egress frame.  If it is, the frame is tagged.
  • If the port is not trusted and a bridge entry for the source MAC of the frame does not exist, the frame is forwarded to CP (control path). CP should add a bridge entry if successfully received and processed (#show datapath bridge table).
  • The LAG flag tells the datapath that the port is a member of a Link Aggregation Group.  The frame is re-labelled, as having ingressed a LAG, not a physical port.
  • Trunk flag labels the port as supporting 802.1Q tagged frames.  If the port is a trunk, the VLAN table is accessed for tagged frames to determine if the port is a member of the specific VLAN.  If not, the frame is dropped.
  • MTU tell what is the allowed MTU on the interface.
  • Ingress ACL will be checked when traffic is coming inbound and processed/dropped accordingly.
  • Engress ACL will be checked when traffic is going outbound and will be sent/dropped accordingly.
  • Session ACL is to create a session for traffic going outbound and will have session created for return traffic, coming inbound.

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Below is the command to check the session ACL.

 

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In A800/2400/200/6x0/7x00 products, this command works correctly and no issues are found in the output. However, when this command is executed in any M3/3x00 controller, default port information for 104 ports is displayed.

 

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The problem is that an Aruba 3x00 controller has only four ports.

 

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Why is information displayed for 100 extra ports? The same thing happens for an M3 that might not have several line cards, but still information is displayed for 104 ports that are not available in the controller.

This issue occurs because the image for the Aruba 3200 family of controllers and the M3 are the same and it is designed so that the correct data path port transaction specific to this kind of controller cannot be recorded.

The port table is statically allocated in the SOS/Datapath (sybite operating system) module. The image for the 3200/3400/3600/M3 products are the same. As such, the table is allocated to support as many ports as the M3 does. To get module entry information and the status of the ports, issue the "show port status" command (as above). The port table of the controller is statically allocated in the SOS module and this module provides common port information for the M3 and 3x00 controllers. Hence in a data path port table, it gives the output for the ports that are not present in the controller at all.

The SOS module was designed to accommodate the maximum port information, which is 24+1 port in each line card. Altogether that makes 104 ports and hence by default it displays output for all 104 ports with reference to the SOS table entry.

This is actually mechanism is working, as it is designed in the image file.

 

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Last update:
‎11-10-2014 06:50 AM
 
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