ASA 5580 flowcontrol send on

zaklina.petkovic · ‎01-18-2011

What are the measurement units for pause_time parameter in the flowcontrol command? The default is 26664 (nanoseconds, KB, or something else?).

Kureli Sankar · ‎01-18-2011

Flow control command was introduced very recently in 8.2.2. This command when implemented on the firewall side (only on ten gig interfaces) and on the switch side, will be able to let the switch know to back off and not send bursty traffic which may otherwise lead to overruns and input errors on the interfaces.

Regarding the "unit" for threshold - I am really not certain. We have filed the below documentation to get this corrected. Thanks for bringing it to our attention.

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCtl72816

http://www.cisco.com/en/US/docs/security/asa/asa82/command/reference/ef.html#wp1952456

Command Default

Pause frames are disabled by default.

The default high watermark is 128 KB.

The default low watermark is 64 KB.

The default pause refresh threshold value is 26664.

ASA5580#sh int t5/0
Interface TenGigabitEthernet5/0 "outside", is up, line protocol is up
Hardware is i82598af rev01, BW 10000 Mbps, DLY 10 usec
Input flow control is unsupported, output flow control is on
Available but not configured via nameif

-KS

Kureli Sankar · ‎02-03-2011

Here is more information:

The pause timer is not necessarily a time value. According to the Ethernet flow
control in IEEE 802.3x, a PAUSE frame includes the period of pause time being
requested, in the form of a 32-bit unsigned integer (0 through 65535). This
number is the requested duration of the pause. The pause time is measured in
units of pause "quanta", where each unit is equal to 512 bit times. So, it is a
counter practically, that is interpreted in time according to the receiving
device time quanta.

The defect link above should display that in the RN (release note).

-KS