onl np router

1 - John DeHart, Jing Lu - 04/21/23

SRAM

ONL NP Router

Rx(2 ME)

HdrFmt(1 ME)

Parse, Lookup,

Copy(3 MEs)

TCAM SRAM

Mux(1 ME)

Tx(1 ME)

QM(1 ME)

xScale xScale

xScale

Assoc. DataZBT-SRAM

Plu

gin

0

Plu

gin

1

Plu

gin

2

Plu

gin

3

Plu

gin

4NN NN NN NN

FreeList Mgr(1 ME)

Tx, QMParsePluginXScale

Stats(1 ME)

QMCopyPlugins SRAM

NN

SRAMRing

ScratchRing

NNRingNN

SRAM

64KW

64KW64KWEach


MUX -> PLC

Flags: Src: Source (2b): 00: Rx 01: XScale 10: Plugin 11: Undefined PT(1b): PassThrough(1)/Classify(0) Reserved (5b)

Reserved (5b)Src(2b)

PT(1b)

01237

PLCMux

L3 (IP, ARP, …) Pkt Length (16b)

Stats Index (16b)

QID(16b)In

Port(3b)

PluginTag(5b)

Flags(8b)

Rsv(4b)

OutPort(4b)

Buffer Handle(24b)


Flags(8b): Why pkt is being sent to XScale TTL(1b): TTL expired Options(1b): IP Options present NoRoute(1b): No matching route or filter NonIP(1b): Non IP Packet received ARP_Needed(1b): NH_IP valid, but no MAC NH_Invalid(1b): NH_IP AND NH_MAC both invalid Reserved(2b): currently unused

PLC -> XScale

PLC

XScale

xScale

SRAML3 (IP, ARP, …)Pkt Length (16b)

Buffer Handle(24b)

Stats Index (16b)

QID(16b)In

Port(3b)

Flags(8b)

PluginTag(5b)

NH MAC DA[47:16] (32b)

NH MAC DA[15:0](16b)

Unicast/MCast bits (16b)

Rsv(8b)

Reserved (16b)

EtherType (16b)

Same as ring_in

Based on Parse &Lookup results

01237

Reserved(2b)

NR(1b)

TTL(1b)

Opt(1b)

NI(1b)

ARP(1b)

NHINV(1b)

45


PLC -> Plugins

PLC

Plugins 0-4

01237

Reserved(2b)

NR(1b)

TTL(1b)

Opt(1b)

NI(1b)

ARP(1b)

NHINV(1b)

45

Flags(8b): Why pkt is being sent to XScale TTL(1b): TTL expired Options(1b): IP Options present NoRoute(1b): No matching route or filter NonIP(1b): Non IP Packet received ARP_Needed(1b): NH_IP valid, but no MAC NH_Invalid(1b): NH_IP AND NH_MAC both invalid Reserved(2b): currently unused

xScale

SRAML3 (IP, ARP, …)Pkt Length (16b)

Buffer Handle(24b)

Stats Index (16b)

QID(16b)In

Port(3b)

Flags(8b)

PluginTag(5b)

NH MAC DA[47:16] (32b)

NH MAC DA[15:0](16b)

Unicast/MCast bits (16b)

Rsv(8b)

Reserved (16b)

EtherType (16b)

Same as ring_in

Based on Parse &Lookup results


PLC -> QM

PLC QM

Buffer Handle(24b)

QID(16b)Rsv(4b)

OutPort(4b)

L3 (IP, ARP, …)Pkt Length (16b)Reserved(16b)

Rsv(8b)

Rsv(8b)

Same as ring_in

Based on Parse & Lookup results

Maybe the added hdr buffer handle


Types of Pkts Arriving at PLC From Rx:

»Only have a payload buf, ref_cnt == 1.»Subject to classification except mal-formed IP pkts detected by

Parse.

From XScale/Plugins:»Passthrough (PT) pkt

May/May not have a hdr buf, ref_cnt >= 1. Not processed by PLC. Copy sends it to QM.

»Non-PT pkt Only have a payload buf at arrival, ref_cnt >= 1. Is IP pkt. Will be classified if it passes IP hdr validation done by Parse.


PLC()PLC(){ if (!ring_in.PT) {

Parse(); if (dlNextBlock != BID_FREELISTMGR) Lookup();}Copy();

}

Inside Copy(), dl_sink() is called to enqueue pkts to downstream blocks.


dl_sink Special design of dl_sink(first, last, try_action)

»“first” == TRUE, means current pkt is the first one of a sequence of pkts to be sunk.

»“last” == TRUE, means current pkt is the last one of a sequence of pkts to be sunk.

»“try_action” == 1, drop the pkt if ring is full; otherwise try till succeeds.»dl_sink() has a return value to indicate if enqueue is successful or not.» If DL_ORDERED is defined and “first” == TRUE, thread waits for signal

from previous context before enqueuing the first pkt.» If DL_ORDERED is defined and “last” == TRUE, thread passes signal to

next context after euqueuing the last pkt.


Parse Functions:

»Do IP Router checks (wrong ver, Hlen, Plen, cksum), count error pkts.»Decrement TTL on pkts from Rx and recompute IP cksum»Detect exceptions (expired TTL, IP option, Non-IP)»Extract lookup key

Input: »ring_in data

Output: » lookup key, dlNextBlock, eth_type, DG QID.

IP DAddr (32b) IP SAddr (32b) DPort (16b)SPort (16b)Proto(8b)

TCPFlags(12b)

Exceptions(16b)

P(3b)

PTag(5b)

140 Bit Key:

RL

PF and AF


Parse Operations:

» If pkt is from Rx: Read eth_type in Ethernet hdr

If eth_type != 0x0800, set NIP in exception bits. – If eth_type == 0x0806, set ARP in exception bits.

Return.»eth_type <= 0x0800.»For pkt from Rx, offset <= 0x18E; for pkt from XScale/plugins, get offset

from payload buf desc. »Read 20B IP hdr.

Check for ver, Hlen, Plen. If fails, count and dlNextBlock <= BID_FREELISTMGR. Return.

If Hlen > 5, set OPT in exception bits, read IP option. Verify cksum. If fails, count and dlNextBlock <= BID_FREELISTMGR. Return. If pkt is from Rx and TTL <= 1, or pkt is from plugins/XScale and TTL < 1, set

TTL in exception bits. If pkt is from Rx and TTL > 1, decrement TTL, recompute cksum and write them

back to dram. Form Datagram QID using DG QID = SA[9:8] SA[6:5] DA[6:5] (Used by Copy in

case of a zero QID). Extract key from IP hdr.

If IP protocol is TCP/UDP, read 14B, and extract key from TCP/UDP hdr. Copy Plugin Tag and In Port to lookup key.


Lookup Key and Results FormatsIP DAddr (32b) IP SAddr (32b) DPort (16b)SPort (16b)

Proto(8b)

TCPFlags(12b)

Exceptions(16b)

P(3b)

PTag(5b)

QID (16b)Stats Index

(16b)

UCastMCast(12b)

V(4b)

Prio(8b)

D(1b)

H(1b)

MH

(1b)

Address (21b)

32 Bit Result in TCAM Assoc. Data SRAM:

96 Bit Result in QDR SRAM Bank0:

PF


(16b)

UniCast(8b)

V(4b)

Res(8b)

D(1b)

H(1b)

MH

(1b)

Address (21b)AF


(16b)

UCastMCast(12b)

V(4b)

Res(8b)

D(1b)

H(1b)

MH

(1b)

Address (21b)RL

SB

(2b)

EntryValid(1b)

NHIP

Valid(1b)

NHMACValid(1b)

IPMC

Valid(1b)

NH_MAC (48b)

NH_IP (32b)Res (16b)

NH_MAC (48b)


NH_MAC (48b)


Multicast Copy Vector (11b)PPS(1b)

•If IP MC Valid = 1

D(1b)

PPS(1b)

UCast Out Port

(3b)

UCast Out Plugin

(3b)

Reserved(4b)


140 Bit Key:

RL

PF and AF

TCAM CtrlBits:

D:DoneH:HIT

MH:Multi-Hit

Res

(2b)


Lookup Overview Initialization

» Control Plane initializes TCAM and Route and Filter DBs Runtime Updates

» Control Plane updates to Route and Filter DBs Design – in upcoming slides Processing – in upcoming slides Lookup will be written in C

» There are many things about writing IXP code in “C” that I need to learn. Here are some of them:

Performing multiple memory operations in parallel and waiting on a set of signals (If needed for performance reasons)

Performing timestamp waits Calling IDT microcode macros


Lookup: Design -- Databases Three Databases:

» Route Lookup: Unicast

Sorted by DAddr Prefix Length Multicast

Exact match on DAddr and prefix of SAddr» Primary Filter

Filters should be sorted in the DB with higher priority filters first» Auxiliary Filter

Filters should be sorted in the DB with higher priority filters first Priority between Primary Filter and Route Lookup

» A priority will be stored with each Primary Filter» A priority will be assigned to RLs (all routes have same priority)» PF priority and RL priority compared after result is retrieved.

One of them will be selected based on this priority comparison. Auxiliary Filters:

» If matched, cause a copy of packet to be sent out according to the Aux Filter’s result.


Lookup: Design -- Results Use SRAM Bank 0 (2 MB per NPU) for Results

»B0 Byte Address Range: 0x000000 – 0x1FFFFF 21 bits

»B0 Word Address Range: 0x000000 – 0x1FFFFC 19 significant bits 2 trailing 0’s

Store result in two parts:»32-bit Associated Data SRAM result for Address of actual Result:

TCAM Control Bits (3b) Done: 1b Hit: 1b MHit: 1b

Priority: 8b Present for Primary Filters, for RL and Aux Filters should be 0

SRAM B0 Word Address: 21b 2 spare bitS if needed for anything else

»3 Words (<= 96 bits) of Result in SRAM Bank0 Use Multi-Database Lookup (MDL) Indirect for searching all 3 DBs

»Order of fields in Key is important. Each thread will need one TCAM context


Lookup Processingwrite KEY to TCAMuse timestamp delay to wait appropriate time

make delay long enough that we are as sure as possible that we willhave to read the 1st word of the Results MB only once

while !DoneBit // DONE Bit BUG Fix requires reading just first wordread 1 word from Results Mailbox and check DoneBit

doneread words 2 and 3 from Results MailboxIf (PrimaryFilter AND RouteLookup results HIT) {

PrimaryResult.Valid TRUEcompare prioritiesstore higher priority result as Primary Result (read result from SRAM Bank0)

} else if (PrimaryFilter results HIT) {PrimaryResult.Valid TRUEPrimaryResults.* PrimaryFilter.* (read result from SRAM Bank0)

} else if (RouterLookup results HIT) {PrimaryResult.Valid TRUEPrimaryResults.* RouteLookup.* (read result from SRAM Bank0)

} else PrimaryResult.Valid Falseif (AuxiliaryFilter result HIT) {

AuxiliaryResult.Valid TRUEAuxiliaryResults.* (read result from SRAM Bank0)

} else AuxiliaryResult.Valid FALSE


Lookup Key and Results FormatsIP DAddr (32b) IP SAddr (32b) DPort (16b)SPort (16b)

Proto(8b)

TCPFlags(12b)

Exceptions(16b)

P(3b)

PTag(5b)


(16b)

UCastMCast(12b)

V(4b)

Prio(8b)

D(1b)

H(1b)

MH

(1b)

Address (21b)

32 Bit Result in TCAM Assoc. Data SRAM:

96 Bit Result in QDR SRAM Bank0:

PF


(16b)

UniCast(8b)

V(4b)

Res(8b)

D(1b)

H(1b)

MH

(1b)

Address (21b)AF


(16b)

UCastMCast(12b)

V(4b)

Res(8b)

D(1b)

H(1b)

MH

(1b)

Address (21b)RL

SB

(2b)

EntryValid(1b)

NHIP

Valid(1b)

NHMACValid(1b)

IPMC

Valid(1b)

NH_MAC (48b)


NH_MAC (48b)


NH_MAC (48b)




D(1b)

PPS(1b)

UCast Out Port

(3b)

UCast Out Plugin

(3b)

Reserved(4b)


140 Bit Key:

RL

PF and AF

TCAM CtrlBits:

D:DoneH:HIT

MH:Multi-Hit

Res

(2b)


Exception Bits in Lookup KeyIP DAddr (32b) IP SAddr (32b) DPort (16b)SPort (16b)

Proto(8b)

TCPFlags(12b)

Exceptions(16b)

P(3b)

PTag(5b)

Non-IP(1b)

140 Bit Key:

RL

PF and AF

ARP(1b)

IP Opt(1b)

TTL(1b)Reserved (12b)

Exception Bits:»TTL: TTL has expired. It was 0 or 1 on arriving packet»IP Opt: IP Packet contained Options»ARP: Ethertype field in ethernet header was ARP»Non-IP: Ethertype field in ethernet header was NOT IP

NOTE: An ARP packet will have ARP bit and Non-IP bit set


Lookup Block Diagram

Setup Lookup Key

Write Lookup Key to TCAM

TimeStamp Delay

Read 1W Result from AD

SRAM Write: 5W

SRAM Read: 1W 150 cycles

mem access Latency

Check Done Bit

ctx_swap

ctx_swap

Read 2W Result from AD SRAM Read: 2W 150 cyclesctx_swap

Read 2 Full Results from QDR SRAM Read: 3W 150 cyclesctx_swap SRAM Read: 3W 150 cycles

Setup Results for Copy

315 cycles

TOTAL (No optimization) 915 cycles


Lookup File locations Code

» src/applications/ONL_Router/src/plc/ONL/lookup.c

Include Paths» src/applications/ONL_Router/src/dispatch_loop/ONL/

dl_source.h and dl_source.c dl_source() and dl_sink() functions

» src/IDT_NSE/data_place_IXP2XXX/include IDT IIPC defines and macros

» others?


Copy Functions:

»Drop error pkts detected by Parse.»Count and send PT pkts to QM. »Process lookup results:

When “control error” (NH_IP and NH_MAC both invalid or both valid), or “ARP request needed” (Uncast pkt with valid NH_IP but invalid NH_MAC), or “no route” (invalid PR and AR) is detected, pkt should be sent to XScale, or one of five plugins, or dropped based on user preference (dynamically configurable).

Compute MAC DAddr for IP multicast pkts. Update total ref_cnt in paylod buf desc for each classified pkt. If total ref_cnt == 1 and pkt goes to QM, fill in payload buf desc with NH_MAC,

Stats index and EtherType. If total ref_cnt > 1, add hdr buf to each pkt going to QM, and fill in hdr buf desc

with buffer_next, packet_size, ref_cnt (=1), NH_MAC, Stats index, EtherType. For each copy, form ring_out data and enqueue it to the outgoing ring.

Input: »ring_in data, exception bits, dlNextBlock, eth_type, DG QID, lookup

results Output:

»Ring_out data


Copy Operations:

»Error pkt detected by Parse (to freelist_mgr): Construct ring_out data to Freelist_mgr Call dl_sink(TRUE, TRUE, 0). Return.

»PT pkt (to QM): dlNextBlock <= BID_QM Construct ring_out data to QM from ring_in data Call dl_sink(TRUE, TRUE, 0). Return.

»Classified pkt: Pre-check:

Copy exception bits to flags. If PR and AR are both invalid, this pkt has no route.

– Set NR bit in flags. – Set dlNextBlock to user preference. – Construct ring_out data. – Call dl_sink(TRUE, TRUE, 1). Return.

Pre-process lookup results, because: Both PR and AR can generate pkt copies to QM and XScale/plugins. Need to know total num of copies to

– Decide whether hdr buffer decs should be added to copy going to QM.– Set “last” bit in dl_sink().– Update total ref_cnt in payload buf desc using one atomic addition.

Post-process lookup results, copy and send pkts to proper rings.


Copy Pre-processing data structure:

struct copy_plugins_prep{ unsigned int pkt_cnt; bool pr_arp; bool pr_nh_inv; bool pr_ucast; bool pr_mcast; bool ar_arp; bool ar_nh_inv; bool ar_ucast;} plugins;


(16b)

UCastMCast(12b)

V(4b)

NH_MAC (48b)



(16b)

UniCast(8b)

V(4b)

SB

(2b)

NH_MAC (48b)


Res

(2b)

PR:

AR:

Pre-process fields

Post-process fields

struct copy_qm_prep{ unsigned int pkt_cnt; bool pr_ucast; bool pr_mcast; bool ar_ucast;} qm;

Only one can be TRUE


Copy (pre-process PR)

If PR is valid, » If NH_IP is valid and NH_MAC is invalid and IP_MC is invalid, this pkt

needs ARP. Set APR bit in flags. If pkt should be sent to XSclae/plugins,

plugins.pkt_cnt ++; plugins.pr_arp <= TRUE.

»Else if NH_IP and NH_MAC are both invalid or both valid, lookup entry is mis-configured.

Set NH_INV bit in flags. If pkt should be sent to XSclae/plugins,

plugins.pkt_cnt ++; plugins.pr_nh_inv <= TRUE.


(16b)

UCastMCast(12b)

V(4b)

EntryValid(1b)

NHIP

Valid(1b)

NHMACValid(1b)

IPMC

Valid(1b)

NH_MAC (48b)




D(1b)

PPS(1b)

UCast Out Port

(3b)

UCast Out Plugin

(3b)

Reserved(4b)



Copy (pre-process PR)»Else,

If MC_valid == 0 (unicast), If Drop == 0,

– If PPS == 0, qm.pkt_cnt ++, qm.pr_ucast <= TRUE.– Else (PPS == 1), plugins.pkt_cnt ++, plugins.pr_ucast <= TRUE.

Else (MC_valid == 1 (Multicast)), If PPS == 0,

– qm.pkt_cnt <= total 1’s in high 5 bits in MCast_copyVector; – plugins.pkt_cnt <= total 1’s in low 6 bits in MCAST_copyVector. – If qm.pkt_cnt > 0, qm.pr_mcast <= TRUE.– If plugins.pkt_cnt > 0, plugins.pr_mcast <= TRUE.

Else (PPS == 1), – plugins.pkt_cnt <= total 1’s in low 6 bits in Mcast_copyVector;– If plugins.pkt_cnt > 0, plugins.pr_mcast <= TURE.


D(1b)

PPS(1b)

UCast Out Port

(3b)

UCast Out Plugin

(3b)

Reserved(4b)


Copy (pre-process AR)

If AR is valid,»If NH_IP is valid and NH_MAC is invalid, this pkt needs ARP.

Set APR bit in flags. If pkt should be sent to XSclae/plugins,

plugins.pkt_cnt ++; plugins.pr_arp <= TRUE.

»Else if NH_IP and NH_MAC are both invalid or both valid, lookup entry is mis-configured.

Set NH_INV bit in flags. If pkt should be sent to XSclae/plugins,

plugins.pkt_cnt ++; plugins.pr_nh_inv <= TRUE.


(16b)

UniCast(8b)

V(4b)

SB

(2b)

NH_MAC (48b)


Res

(2b)

EntryValid(1b)

NHIP

Valid(1b)

NHMACValid(1b)

IPMC

Valid(1b)

D(1b)

PPS(1b)

UCast Out Port

(3b)

UCast Out Plugin

(3b)


Copy (pre-process AR)

»Else, Each SB value is associated with a sampling rate rt(SB) that is

dynamically configurable by users. Generate a random number rd. If rd <= rt(SB),

If PPS == 0, – qm.ar_ucast <= TRUE, qm.pkt_cnt ++.

Else (PPS == 1), – plugins.ar_ucast <= TRUE, plugins.pkt_cnt ++.

D(1b)

PPS(1b)

UCast Out Port

(3b)

UCast Out Plugin

(3b)

Rsv(2b)

SB(2b)


Copy (post-process)

If qm.pkt_cnt + plugins.pkt_cnt == 0, dlNextBlock <= BID_FREELISTMGR, dl_sink(TRUE, TRUE, 0). Return.

Read ref_cnt from payload buf desc. If qm.pkt_cnt + plugins.pkt_cnt + (ref_cnt – 1) == 1,

» If qm.pkt_cnt == 1, DO NOT add hdr buf desc. Based on qm.pr_ucast, qm.pr_mcast, qm.ar_ucast,

Fill in NH_MAC, stats index, and eth_type in payload buf desc. Construct QM ring_out data. dlNextBlock <= BID_QM. dl_sink(TRUE, TRUE, 0). Return.

» Else (plugins.pkt_cnt == 1), Based on plugins.*,

construct plugins/XScale ring_out data. Set dlNextBlock to XScale or one of the five plugins. dl_sink(TRUE, TRUE, 1). Return.

struct copy_plugins_prep{ unsigned int pkt_cnt; bool pr_arp; bool pr_nh_inv; bool pr_ucast; bool pr_mcast; bool ar_arp; bool ar_nh_inv; bool ar_ucast;} plugins;

struct copy_qm_prep{ unsigned int pkt_cnt; bool pr_ucast; bool pr_mcast; bool ar_ucast;} qm;


(16b)

UCastMCast(12b)

V(4b)

NH_MAC (48b)



(16b)

UniCast(8b)

V(4b)

SB

(2b)

NH_MAC (48b)


Res

(2b)

PR:

AR:


Copy (post-process) Else (qm.pkt_cnt + plugins.pkt_cnt + (ref_cnt – 1) > 1),

»Add (qm.pkt_cnt + plugins.pkt_cnt – 1) to ref_cnt in payload buf desc.» If qm.pkt_cnt >0,

for each copy to QM, add hdr buf desc. Based on qm.pr_ucast, qm.pr_mcast, qm.ar_ucast,

Fill in buffer_next, packet_size, ref_cnt (=1), NH, stats index, and eth_type in hdr buf desc.

Construct QM ring_out data. dlNextBlock <= BID_QM. Call dl_sink() qm.pkt_cnt times.

– If plugins.pkt_cnt == 0, Set “last” bit in dl_sink() for the last copy and return. » If plugins.pkt_cnt > 0,

Based on plugins.*, Construct plugins/XScale ring_out data. Set dlNextBlock to XScale or one of the five plugins. Call dl_sink() plugins.pkt_cnt times.

– Set “last” bit in dl_sink() for the last copy and return.


PLC Typical Case Valid IP Pkt from Rx, no option, go to one port as a result of PR. AR entry is

invalid.

Read eth_type, IP, TCP/UDP hdr

Aligned 10LW DRAM read

300

Operation

Memory Access

Cycle Count

Write TTL, IP cksum Aligned 4LW DRAM write

300 Parse

Write NH MAC, stats index, eth_type Aligned 3LW SRAM

write 150

Enqueue pkt to QM 3LW Scratch Ring write 60

Copy

Lookup 915 Lookup

Total: 1785

Dequeue pkt from MUX 3LW Scratch Ring read 60

dl_sink

dl_source

onl np router

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