1. ONL NP Router xScale xScale TCAM SRAM Rx (2 ME) Mux (1 ME) Parse,
Assoc. Data
ZBT-SRAM
SRAM
64KW Rx
(2 ME)
Mux
(1 ME)
Parse,
Lookup,
Copy
(3 MEs) QM
(1 ME)
HdrFmt
(1 ME) Tx
(1 ME) NN
64KW
SRAM
64KW
Each
SRAM
Ring NN NN NN NN
Plugin0
Plugin1
Plugin2
Plugin3
Plugin4
Scratch
Ring
xScale
SRAM NN NN
Ring
Stats
(1 ME) QM
Copy
Plugins
SRAM
FreeList Mgr
(1 ME)
Tx, QM
Parse
Plugin
XScale

2. ONL SRAM Buffer Descriptor
Buffer_Next (32b)
LW0
Buffer_Size (16b)
Offset (16b)
LW1
Packet_Size (16b)
Free_list
0000
(4b)
Reserved
(4b)
Ref_Cnt
(8b)
LW2
Stats Index (16b)
MAC DAddr_47_32 (16b)
LW3
MAC DAddr_31_00 (32b)
LW4
EtherType (16b)
Reserved (16b)
LW5
Reserved (32b)
LW6
Packet_Next (32b)
LW7
1 Written by Rx,
Added to by Copy
Decremented by
Freelist Mgr
Ref_Cnt
(8b)
Written by Freelist Mgr
Written by Rx
Written by Copy
Written by Rx and Plugins
Written by QM

3. MUX -> PLC
Flags:
Src: Source (2b):
00: Rx
01: XScale
10: Plugin
11: Undefined
PT(1b): PassThrough(1)/Classify(0)
Reserved (5b)
L3 (IP, ARP, …) Pkt
Length (16b)
Stats Index (16b)
QID(16b) In
Port
(3b)
Plugin
Tag
(5b)
Flags
(8b)
Rsv
(4b)
Out
Buffer Handle(24b)
PLC
Mux
Reserved (5b)
Src
(2b) PT
(1b) 1 2 3 7
Assume QID is user visible QID – low 13 bits are valid

4. PLC -> XScale
XScale
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
SRAM
L3 (IP, ARP, …)
Pkt Length (16b)
Buffer Handle(24b)
Stats Index (16b)
QID(16b) In
Port
(3b)
Flags
(8b)
Plugin
Tag
(5b)
NH MAC DA[47:16] (32b)
NH MAC DA[15:0]
(16b)
Unicast/MCast bits
Rsv
Reserved (16b)
EtherType (16b)
Same as ring_in
Based on Parse &
Lookup results
Assume QID is user visible QID – low 13 bits are valid
Port number(s) is available in Unicast/Mcast bits
PLC 1 2 3 7
Reserved
(2b) NR
(1b)
TTL
Opt NI
ARP NH
INV 4 5

5. PLC -> Plugins
xScale
SRAM
L3 (IP, ARP, …)
Pkt Length (16b)
Buffer Handle(24b)
Stats Index (16b)
QID(16b) In
Port
(3b)
Flags
(8b)
Plugin
Tag
(5b)
NH MAC DA[47:16] (32b)
NH MAC DA[15:0]
(16b)
Unicast/MCast bits
Rsv
Reserved (16b)
EtherType (16b)
Same as ring_in
Based on Parse &
Lookup results
PLC
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
Assume QID is user visible QID – low 13 bits are valid
Port number(s) is available in Unicast/Mcast bits 1 2 3 7
Reserved
(2b) NR
(1b)
TTL
Opt NI
ARP NH
INV 4 5
Plugins 0-4

6. PLC -> QM PLC QM Buffer Handle(24b) QID(16b) Reserved(16b)
Rsv
(4b)
Out
Port
L3 (IP, ARP, …)
Pkt Length (16b)
Reserved(16b)
(8b)
PLC QM
Same as ring_in
Based on Parse & Lookup results
Maybe the added hdr buffer handle

7. Types of Pkts Arriving at PLC
From Rx:
Only have a payload buf, ref_cnt == 1.
To be classified except IP pkts with mal-formed hdr (these pkts will be counted and dropped by PLC).
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.
To be classified if it passes IP hdr validation; otherwise, pkt gets counted and dropped by PLC.

8. PLC() PLC() { dlNextBlock = BID_QM; //default downstream block
if (!ring_in.PT) {
Parse();
if (dlNextBlock != BID_FREELISTMGR)
Lookup(); }
Copy();
Inside Copy(), dl_sink() is called to enqueue pkts to downstream blocks.

9. 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 operation 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.

10. Where are the files located?
PLC:
ONL_Router\src\plc\ONL\plc[.c.h]
Parse and Copy:
ONL_Router\src\plc\ONL\parse[.c.h]
ONL_Router\src\plc\ONL\copy[.c.h]
Dispatch_loop:
ONL_Router\src\dispatch_loop\ONL\plc_dl.c
ONL_Router\src\dispatch_loop\ONL\dl_source[.c.h]
Ring related C functions:
ONL_Router\src\dispatch_loop\ONL\ring_formats.h
ONL_Router\src\dispatch_loop\ONL\sram_rings_WU[.c.h]
ONL_Router\src\dispatch_loop\ONL\scratch_rings_WU[.c.h]
ONL_Router\src\dispatch_loop\ONL\nn_rings[.c.h]

11. Parse Functions: Input: Output:
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.
Non-IP
(1b)
ARP
IP Opt
TTL
Reserved (12b)
IP DAddr (32b)
IP SAddr (32b) P
Tag
(5b) P
(3b)
Proto
(8b)
DPort (16b)
SPort (16b)
Exceptions
(16b)
TCP
Flags
(12b)
140 Bit Key: RL
PF and AF

12. Parse Operations: If pkt is from Rx: eth_type <= 0x0800.
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.

13. Pseudo code - parse() parse() { //process typical case first
if (pkt is from RX) {//L3 pkt hdr starts from offset 0x18E in dram pkt buffer
read 16W from dram buffer offset 0x188; //this will read eth_type
if (pkt is IPv4) {
dg_qid = SA[9:8]SA[6:5]DA[6:5];
if (pkt has correct IP version, hdr length and pkt length) {
if (pkt has no option) {
compute cksum;
if (cksum is correct) {
if (TTL > 1) {
decrement TTL and re-compute cksum;
write new TTL and cksum back to dram pkt buffer;
construct lookup key;
return; }
else {//TTL <= 1
construct lookup key and set TTL bit in exception bits;
else {//cksum is wrong
count the pkt and set dlNextBlock to BID_FREELISTMGR;

14. Pseudo code - parse() else {//pkt has option
read 6 more words from dram pkt buffer and align IP/TCP hdr;
based on hdr length, compute cksum;
if (cksum is correct) {
if (TTL > 1) {
decrement TTL and re-compute cksum;
write new TTL and cksum back to dram pkt buffer;
construct lookup key;
return; }
else {//TTL <= 1
construct lookup key and set TTL bit in exception bits;
else {//cksum is wrong
count the pkt and set dlNextBlock to BID_FREELISTMGR;
else {//pkt has wrong IP version, or hdr length or pkt length

15. Pseudo code - parse() else {//pkt is not IPv4
construct lookup key and set NI bit in exception bits;
if (it is an ARP pkt) {
set ARP bit in exception bits; }
return;
else {//pkt is from plugins or XScale
read 22W from dram pkt buffer starting from IP pkt hdr, and align IP/TCP hdr;
dg_qid = SA[9:8]SA[6:5]DA[6:5];
if (pkt has correct IP version, hdr length and pkt length) {
if (pkt has no option) {
compute cksum;
if (cksum is correct) {
construct lookup key;
if (TTL == 0) {
set TTL bit in exception bits;
else {//cksum is wrong
count the pkt and set dlNextBlock to BID_FREELISTMGR;

16. Pseudo code - parse() else {//pkt has option
based on hdr length, compute cksum;
if (cksum is correct) {
construct lookup key;
if (TTL == 0) {
set TTL bit in exception bits; }
return;
else {//cksum is wrong
count the pkt and set dlNextBlock to BID_FREELISTMGR;
else {//pkt has wrong IP version, or hdr length or pkt length

17. Lookup Key and Results Formats
IP DAddr (32b)
IP SAddr (32b) P
Tag
(5b) P
(3b)
Proto
(8b)
DPort (16b)
SPort (16b)
Exceptions
(16b)
TCP
Flags
(12b)
140 Bit Key: RL
PF and AF
32 Bit Result in TCAM
Assoc. Data SRAM:
96 Bit Result in
QDR SRAM Bank0: PF
Prio
(8b) D
(1b) H M
Address (21b) V
(4b)
UCast
MCast
(12b)
QID (16b)
Stats Index
(16b)
NH_MAC (48b)
NH_IP (32b)
Res (16b) AF
Res
(8b) D
(1b) H M
Address (21b) V
(4b) S B
(2b) R e s
(2b)
Uni
Cast
(8b)
QID (16b)
Stats Index
(16b)
NH_MAC (48b)
NH_IP (32b)
Res (16b) RL
Res
(8b) D
(1b) H M
Address (21b) V
(4b)
UCast
MCast
(12b)
QID (16b)
Stats Index
(16b)
NH_MAC (48b)
NH_IP (32b)
Res (16b)
TCAM Ctrl
Bits:
D:Done
H:HIT
MH:Multi-Hit
Entry
Valid
(1b) NH IP
MAC MC D
(1b)
PPS
UCast
Out Port
(3b)
Out Plugin
Reserved
(4b)
If IP MC Valid = 0
Multicast Copy Vector (11b)
PPS
(1b)
If IP MC Valid = 1

18. Copy Functions: Input: Output: 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 in lookup key, dlNextBlock, eth_type, DG QID, lookup results
Output:
Ring_out data

19. Copy Control Block Located in SRAM (COPY_BLOCK_CONTROL_MEM_BASE)
Dynamically configurable through XScale control software
A sampling rate must be an integer between 0 and 0x7FFF (largest random number)
typedef __declspec(packed) union _sampling_rate {
struct {
unsigned int sp_rate_00;
unsigned int sp_rate_01;
unsigned int sp_rate_10;
unsigned int sp_rate_11; };
unsigned int i[4];
} sampling_rate;
typedef __declspec(packed) struct _user_preference
unsigned int no_route : 3;// "000" ~ "100" - plugin_0 ~ plugin_4, "101" - XScale, "111" - drop
unsigned int arp_needed : 3;
unsigned int nh_inv : 3;
} user_pref;
typedef struct _copy_control_block
sampling_rate sp_rate;
user_pref pref;
} copy_control_block;

20. 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
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.

21. Copy Pre-processing data structure: struct copy_qm_prep{
unsigned int pkt_cnt;
bool pr_ucast;
bool pr_mcast;
bool ar_ucast;
} qm;
PR:
QID (16b)
Stats Index
(16b)
UCast
MCast
(12b) V
(4b)
NH_MAC (48b)
NH_IP (32b)
Res (16b)
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;
AR:
QID (16b)
Stats Index
(16b)
Uni
Cast
(8b) V
(4b) S B
(2b)
NH_MAC (48b)
NH_IP (32b)
Res (16b) R e s
Pre-process fields
Post-process fields
Only one can be TRUE

22. Multicast Copy Vector (11b)
Copy (pre-process PR) V
(4b)
UCast
MCast
(12b)
QID (16b)
Stats Index
(16b)
NH_MAC (48b)
NH_IP (32b)
Res (16b)
Entry
Valid
(1b) NH IP
MAC MC D
(1b)
PPS
UCast
Out Port
(3b)
Out Plugin
Reserved
(4b)
If IP MC Valid = 0
Multicast Copy Vector (11b)
PPS
(1b)
If IP MC Valid = 1
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.
plugins.pkt_cnt ++; plugins.pr_nh_inv <= TRUE.

23. Multicast Copy Vector (11b)
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
UCast
Out Port
(3b)
Out Plugin
Reserved
(4b)
Multicast Copy Vector (11b)
PPS
(1b)

24. Copy (pre-process AR) If AR is valid,
QID (16b)
Stats Index
(16b)
Uni
Cast
(8b) V
(4b) S B
(2b)
NH_MAC (48b)
NH_IP (32b)
Res (16b) R e s
Entry
Valid
(1b) NH IP
MAC MC D
(1b)
PPS
UCast
Out Port
(3b)
Out Plugin
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.
plugins.pkt_cnt ++; plugins.pr_nh_inv <= TRUE.

25. Copy (pre-process AR) Else,D
(1b)
PPS
UCast
Out Port
(3b)
Out Plugin
Rsv
(2b) SB
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 ++.

26. Copy (post-process) PR: AR:
struct copy_qm_prep{
unsigned int pkt_cnt;
bool pr_ucast;
bool pr_mcast;
bool ar_ucast;
} qm;
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;
QID (16b)
Stats Index
(16b)
UCast
MCast
(12b) V
(4b)
NH_MAC (48b)
NH_IP (32b)
Res (16b)
AR:
QID (16b)
Stats Index
(16b)
Uni
Cast
(8b) V
(4b) S B
(2b)
NH_MAC (48b)
NH_IP (32b)
Res (16b) R e s
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.

27. 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.

28. Pseudo code - copy() copy() { //process typical case first
if (it is a normal unicast pkt from RX, and PR is valid with invalid NH_IP and valid NH_MAC, and AR is invalid ) {
write to payload buffer desc with stats_index, NH_MAC and eth_type;
prepare QM ring data; //in qid, 3-bit port is numbered from 1 to 5, while port in lookup result is from 0 to 4
update pre-Q counter by writing to stats ring;
enqueue pkt to QM ring;
return; }
//process all other cases
drop error pkt by writing buf handle to Freelist_mgr ring; return;
send PT pkt to QM, update pre-Q counter, and enqueue pkt to QM ring; return;
//pre-check for invalid PR and AR
if (both PR and AR are invalid) {
set dlNextBlock to user preference, and construct ring data;
enqueue pkt to the specified ring;
if (ring is full and pkt gets dropped) {
update drop counter by writing to stats ring;

29. Pseudo code - copy() //pre-process lookup results
initialize qm_copy and plugins_copy; //qm_copy and plugins_copy store pre-processing results
//pre-process PR
if (PR is valid ) {
if (it’s unicast with valid NH_IP and invalid NH_MAC) {//ARP is needed
if (pkt shouldn’t be dropped based on user preference) {
plugins_copy.pkt_cnt++; plugins_copy.pr_arp = TRUE; }
else if (it’s unicast with NH_IP and NH_MAC both valid or both invalid) {//lookup entry is mis-configured
plugins_copy.pkt_cnt++; plugins_copy.pr_nh_inv = TRUE;
else {//process uc_mc_bits
if (it’s unicast pkt) {
if (no drop) {
if (PPS == 0) {//port unicast
qm_copy.pkt_cnt++; qm_copy.pr_ucast = TRUE;
else {//plugin unicast
plugins_copy.pkt_cnt++; plugins_copy.pr_ucast = TRUE;

30. Pseudo code - copy() else {//multicast
if (PPS == 0) {//port and plugin multicast
qm_copy.pkt_cnt = number of 1’s in high 5 bits of uc_mc_bits;
if (qm_copy.pkt_cnt != 0) {
qm_copy.pr_mcast = TRUE; }
plugins_copy.pkt_cnt = number of 1’s in low 6 bits of uc_mc_bits;
if (plugins_copy.pkt_cnt != 0) {
plugins_copy.pr_mcast = TRUE;
else {//plugin multicast

31. Pseudo code - copy() //pre-process AR if (AR is valid ) {
if (pkt has valid NH_IP and invalid NH_MAC) {//ARP is needed
if (pkt shouldn’t be dropped based on user preference) {
plugins_copy.pkt_cnt++; plugins_copy.ar_arp = TRUE; }
else if (NH_IP and NH_MAC both valid or both invalid) {//lookup entry is mis-configured
plugins_copy.pkt_cnt++; plugins_copy.ar_nh_inv = TRUE;
else {//process uc_bits
generate a rand number rd;
if (PPS == 0) {//port unicast
if (rd <= sp_rate) {//compare rd with sampling rate sp_rate associated with sp_bits;
qm_copy.pkt_cnt++; qm_copy.ar_ucast = TRUE;
else {//plugin unicast
plugins_copy.pkt_cnt++; plugins_copy.ar_ucast = TRUE;

32. Pseudo code - copy() //post-process
if (qm_copy.pkt_cnt == 0 and plugins_copy.pkt_cnt == 0) {//no copy is made, drop the pkt
set dlNextBlock = BID_FREELISTMGR;
drop pkt by writing buf handle to Freelist_mgr ring;
update drop counter by writing to stats ring;
return; }
if (ref_cnt == 1) {//only one copy is made
if (qm_copy.pkt_cnt == 1) {//pkt goes to QM
if (qm_copy.pr_ucast == TRUE) {//unicast pkt resulted from PR
write to payload buffer desc with stats_index, NH_MAC and eth_type;
prepare QM ring data;
update pre-Q counter by writing to stats ring;
else (qm_copy.pr_mcast == TRUE) {//multicast pkt resulted from PR
compute multicast NH_MAC;
based on port number, prepare QM ring data;
else {//unicast pkt resulted from AR
enqueue pkt to QM ring;

33. Pseudo code - copy() else {//pkt goes to plugins/XScale
if (plugins_copy.pr_arp == TRUE) {//APR needed resulted from PR
set dlNextBlock to user preference, and construct ring data; }
else if (plugins_copy.pr_nh_inv == TRUE) {//NH_INV resulted from PR
else if (qm_copy.pr_ucast == TRUE) {//unicast pkt resulted from PR
set dlNextBlock to one of the plugins/XScale, and construct ring data;
else (qm_copy.pr_mcast == TRUE) {//multicast pkt resulted from PR
set dlNextBlock to one of the plugins/XScale, and construct ring data; //use multicast NH_MAC
else if (plugins_copy.ar_arp == TRUE) {//APR needed resulted from AR
else if (plugins_copy.ar_nh_inv == TRUE) {//NH_INV resulted from AR
else {//unicast pkt resulted from AR
set dlNextBlock to the plugins/XScale specified in uc_bits, and construct ring data;
enqueue pkt to the ring specified in dlNextBlock;
if (ring is full and pkt gets dropped) {
update drop counter by writing to stats ring;
return;

34. Pseudo code - copy() else {//multiple copies are made
update ref_cnt in payload buffer desc;
if (qm_copy.pkt_cnt > 0) {//at least one pkt goes to QM
set dlNextBlock to BID_QM;
if (qm_copy.pr_ucast == TRUE) {//unicast pkt resulted from PR
allocate a hdr buffer desc;
write to hdr buffer desc with buffer next, L3 pkt length, ref_cnt, stats_index, NH_MAC, eth_type;
prepare QM ring data, and enqueue pkt to QM;
update pre-Q counter by writing to stats ring; }
else if (qm_copy.pr_mcast == TRUE) {//multicast pkt(s) resulted from PR
compute multicast NH_MAC;
for (each output port set in uc_mc_bits) {
write to payload buffer desc with stats_index, NH_MAC and eth_type;
based on port number, prepare QM ring data;
enqueue pkt to QM ring;
if (qm_copy.ar_ucast == TRUE) {//unicast pkt resulted from AR

35. Pseudo code - copy()
if (plugins_copy.pkt_cnt > 0) {//at least one pkt goes to plugins/XScale
if (plugins_copy.pr_arp == TRUE) {//APR needed resulted from PR
set dlNextBlock to user preference, construct ring data, and enqueue pkt;
if (ring is full and pkt gets dropped) {
update drop counter by writing to stats ring; }
else if (plugins_copy.pr_nh_inv == TRUE) {//NH_INV resulted from PR
else if (qm_copy.pr_ucast == TRUE) {//unicast pkt resulted from PR
set dlNextBlock to the plugins/XScale specified in uc_mc_bits;
construct ring data, and enqueue pkt;
else if (qm_copy.pr_mcast == TRUE) {//multicast pkt(s) resulted from PR
compute multicast NH_MAC, and construct ring data;
for (each plugin/XScale set in uc_mc_bits) {
set dlNextBlock, and enqueue pkt;

36. Pseudo code - copy()
if (plugins_copy.ar_arp == TRUE) {//APR needed resulted from AR
set dlNextBlock to user preference, construct ring data, and enqueue pkt;
if (ring is full and pkt gets dropped) {
update drop counter by writing to stats ring; }
else if (plugins_copy.ar_nh_inv == TRUE) {//NH_INV resulted from AR
else if {//unicast pkt resulted from AR
set dlNextBlock to the plugins/XScale specified in uc_bits;
construct ring data, and enqueue pkt;
return;

37. Estimated latency for PLC Typical Case
Typical case: Valid IP Pkt from Rx, no option, goes to one port as a result of PR. AR entry is invalid.
Operation
Memory Access
Cycle Count
dl_source
Dequeue pkt from MUX
Scratch Ring read: 3W 60
Read eth_type, IP, TCP/UDP hdr
DRAM read: 16W
300
Parse
Write TTL, IP cksum
DRAM write: 4W
300
Lookup
Lookup
915
Write NH MAC, stats index, eth_type
Copy
SRAM write: 3W
150
dl_sink
Enqueue pkt to QM
Scratch Ring write: 3W 60
Total:
1785

38. PLC performance (typical case)
System is unloaded, 8 threads per ME
Processing time: 330 cycles
Idle time: 1354 cycles

39. Tests Performed Parse: Typical case:
Pkt from Rx, no error, no option, no exception.

40. Tests Performed Copy: Typical case: Unicast case: Multi-copy cases:
Valid PR with port unicast, invalid AR
Unicast case:
Valid PR with plugin unicast, invalid AR
Multi-copy cases:
Valid PR with port/plugins multicast, invalid AR
5 copies go to 5 output ports
7 copies go to one output port, 5 plugins and XScale
Valid PR with plugins multicast, invalid AR
6 copies go to 5 plugins and XScale
Exception cases:
Invalid PR and invalid AR (no route): drop pkt
Valid PR, unicast, ARP needed: send pkt to XScale
Valid PR, unicast, NH invalid:send pkt to XScale
Valid PR, unicast with drop bit set; invalid AR: drop pkt