Meaning of FFP in packet-drop

[manuel.bitzi]

Hi all

Given the following output:

<Sysname> display packet-drop interface gigabitethernet 1/0/1

GigabitEthernet1/0/1:

Packets dropped by GBP full or insufficient bandwidth: 301

Packets dropped by FFP: 261

Packets dropped by STP non-forwarding state: 321

Does somebody know what "dropped by FFP" means? FFP is Fast Filter Processor. But what does it mean and when will it be triggered?

Regards,

Manuel

[Gillespie]

I wouldbe interested in this answer as well in regards to this output:

> [T-Gate-Internal]disp packet-drop summ All interfaces: 
> Packets dropped by GBP full or insufficient bandwidth: 32614456 
> Packets dropped by FFP: 177090329 Packets dropped by STP 
> non-forwarding state: 95 

[NicoNico]

This article explains it.

Bests

[DhritimanDas]

FPP is :

A fast filtering processor (FFP) is incorporated into the EPICs and GPICs, in order to accelerate packet forwarding and enhance packet flow. The FFP is essentially a state machine driven programmable rules engine. Filters are applied to packets received by the FFP, through the use of masks so that certain fields of a packet may be evaluated. The filters utilized by FFP are defined by a rules table, where that table is completely programmable by the CPU, through the CMIC. The actions taken based on the filtering of the FFP include 802.1p tag insertion, 802.1p priority mapping, IP TOS (type-of-service) tag insertion, sending of the packet to the CPU, discarding or dropping of the packet and forwarding the packet to an egress port.

The FFP counters do not necessarily mean that its dropping the data packet in their network, it is something the switch CPU decides and cannot be user manipulated. It enables switch applications to set filters on some of the important fields from Layer 2 to layer 7 of the packet. The filters are used mainly for packet classification based on certain protocol fields in the packets. Based on packet classification various actions can be taken. Two classes of actions are defined: In-Profile Actions and Out-Profile Actions. When a packet is in in-profile, the actions associated with the in-profile are taken. When the packet is out of profile, the actions associated with out-profile actions are taken. Some of the actions may involve discarding the packets, sending the packet to the CPU, sending the packet to Mirrored-to Port, sending the packet on certain COS priority queue, changing the type Of Service (TOS Precedence), remarking DSCP etc.

Please check the below link which provides a detailed explanation of FFP mechanism, specifically check for (Fast Filter Processing) on the document:

Click here to refer to the technical article "Gigabit Switch With Frame Forwarding And Address Learning - Patent 7046679".

Burst-mode enable might resolve the issue.

<Sysname> system-view
[Sysname] burst-mode enable