Skip to content

Interface configuration on Wedge 100BF-32

This section describes how to configure interface via RARE/freeRtr OS. Interfaces can be seen from 3 perspectives:

  • Front panel
  • INTEL/TOFINO ASIC
  • freeRtr

Front panel

On Wedge100bf32, all ports are accessible via the switch front panel. Actually, all QSFP28 ports are labelled and are visually identified by an index that belongs to [1..32] range. All ports are able to run at 10/25/40/100GE speeds. Each QSFP28 port has also 4 lanes. It is also possible for each port to provide 4x10GE, 4x25GE, and maybe 2x40GE interfaces using a breakout cable.

Therefore each port/lane will have the following identifier: $FRONT_PANEL_PORT/$LANE

For example, if you have a 4x25GE breakout cable inserted in FRONT PANEL PORT 1, the interfaces will be identified as follow:

FRONT PANEL 15/0, 15/1,15/2, 15/3.

INTEL/TOFINO ASIC

Internally, INTEL/TOFINO ASIC allocates to each interface (i.e $PORT/$LANE pair) a specific identifier. The output from bf_shell utility below shows an example of interface mapping.

-----+----+---+----+-------+----+--+--+---+---+---+--------+----------------+----------------+-
PORT |MAC |D_P|P/PT|SPEED  |FEC |AN|KR|RDY|ADM|OPR|LPBK    |FRAMES RX       |FRAMES TX       |E
-----+----+---+----+-------+----+--+--+---+---+---+--------+----------------+----------------+-
1/0  |23/0|132|3/ 4|10G    |NONE|Au|Au|YES|ENB|UP |  NONE  |           55055|           55154|
1/1  |23/1|133|3/ 5|-------|----|--|--|YES|---|---|--------|----------------|----------------|-
1/2  |23/2|134|3/ 6|-------|----|--|--|YES|---|---|--------|----------------|----------------|-
1/3  |23/3|135|3/ 7|-------|----|--|--|YES|---|---|--------|----------------|----------------|-

Note

The output above is just for information. Practically you would never have to run bf_shell in order to retrieve this mapping between front panel interface and TOFINO identifier

freeRtr

freeRtr identifies dataplane port as sdn<index> interface. <index> is an integer.

Note

As a rule of thumb, when no breakout cable is used, <index> is the front panel port identifier: <fp_port_id>. If a breakout cable is used <index> can be the concatenation of [<fp_port_id> & 00 & <lane_id>]

For example, if a module is inserted into front panel port 1, then freeRtr interface name is interface sdn1. If a 4x25GE breakout cable is plugged into port 1, then interface name should be: interface sdn1001, sdn1002,sdn1003, sdn1004

Interface configuration

In freeRtr philosophy, each interface belongs to either a vrf or a bridge. It is therefore mandatory:

  • to configure a vrf or a bridge 
    vrf definition <MY_VRF>
 exit

    bridge <BRIDGE_ID>
 mac-learn
 exit

  • and bind each of them to an interface. 

    conf t
interface sdn1
 vrf forwarding  <MY_VRF_ID>
 exit
end

    conf t
interface sdn2
 bridge-group <MY_BRIDGE_ID>
 exit
end

  • Declare vrf or bridge and interfaces at the dataplane level 

    server p4lang <SERVER_P4_ID>
 export-vrf <MY_VRF_ID> 1
 export-bridge <MY_BRIDGE_ID> 1
 export-port sdn1 132 100 0 0 0
 export-port sdn2 140 100 0 0 0
 exit
end

Explanation

The above example describe the configuration of front panel port 1 and 2.

  • Front panel port 1 (sdn1) is bound to vrf <MY_VRF_ID>
  • Front panel port 2 (sdn2) is bound to bridge <MY_VRF_ID>

The interesting part is server p4lang p4 configuration stanza

  • export-vrf <MY_VRF_ID> <DATAPLANE_VRF_ID>

    • <MY_VRF_ID> let's assign a value: my_vrf
    • <DATAPLANE_VRF_ID> let's assign a value: 1

  • export-bridge <MY_BRIDGE_ID> DATAPLANE_BRIDGE_ID

    • <MY_BRIDGE_ID> let's assign a value: 1
    • <DATAPLANE_BRIDGE_ID> let's assign a value: 1

  • export-port <FREERTR_INTF> <TOFINO_PORT_ID> <PORT_SPEED> <FEC> AUTONEG <FLOWCTRL>

    • <FREERTR_INTF>: freeRtr sdn interface identifier
    • <TOFINO_PORT_ID>: INTEL/TOFINO ASIC port identifier
    • <PORT_SPEED>: Port speed 10/25/40/100 GE
    • <FEC>: Forwarding Error Correction in use [0=UNDEFINED, 1=NONE, 2=FC, 3=RS]
    • <AUTONEG>: Autonegotiation [0=UNDEFINED, 1=OFF, 2=ON]
    • <FLOWCTRL>: Flow control type [0=UNDEFINED, 1=NONE, 2=PAUSE, 3=PFC]

Note

In the above example <TOFINO_PORT_ID> for front panel port 1 has value 132.

How do we get this value without bf_shell ?

  • 2 possibilities:

-1- show p4lang <SERVER_P4_ID> 

FREERTR# show p4lang p4
...
front  name
...
132    frontpanel-1/0
133    frontpanel-1/1
134    frontpanel-1/2
135    frontpanel-1/3
...
140    frontpanel-2/0
141    frontpanel-2/1
142    frontpanel-2/2
143    frontpanel-2/3
...
-2- Use freeRtr configuration auto-completion 
conf t
FREERTR(cfg)#server p4lang p4
FREERTR(cfg-server)#export-port sdn4 ?
  <num>           - port number
  dynamic         - dynamic port number
  frontpanel-1/0  - port number
  frontpanel-1/1  - port number
  frontpanel-1/2  - port number
  frontpanel-1/3  - port number
...
If -2- is used then frontpanel-1/0 will be translated to its corresponding TOFINO identifier (i.e 132).

The final configuration is:

conf t
!
vrf definition my_vrf
 exit
!
bridge 1
 mac-learn
 exit
!
interface sdn1
 vrf forwarding my_vrf
 exit
!
interface sdn2
 bridge-group 1
 exit
!
server p4lang p4
 export-vrf my_vrf 1
 export-bridge 1 1
 export-port sdn1 132 100 0 0 0
 export-port sdn2 140 100 0 0 0
 exit
!
end