John DeHart and James Moscola (Original FastPath Design) August 2008 Flow Stats Module -- Control
Jan 07, 2016
John DeHart and
James Moscola (Original FastPath Design)August 2008
Flow Stats Module--
Control
2 - Flow Stats Module – John DeHart and James Moscola
SPP V1 LC Egress with 1x10Gb/s Tx
SWITCH
MSF
Rx1
RBUF
Rx2Key
ExtractLookup
HdrFormat
FlowStats1NN
1x10GTx1
NN1x10G
Tx2
MSF
TBUF
NNNN NN NN
RTM
Stats(1 ME) SRAM3SCR SRAM1
SRAM2
NN
FlowStats2
TCAM
XScale
SC
R
XScale
NAT MissScratch Ring
XScale
NAT Pktreturn
SC
R
SRAMArchive Records
PortSplitter
QM0 SCR
QM1 SCR
QM2 SCR
QM3 SCR
SCR
SR
AM
Freelist
3 - Flow Stats Module – John DeHart and James Moscola
SPP V1 LC Egress with 10x1Gb/s Tx
SWITCH
MSF
Rx1
RBUF
Rx2Key
ExtractLookup
HdrFormat
MSF
TBUF
NNNN NN NN
RTM
NN
SC
R
XScale
NAT MissScratch Ring
TCAM
5x1GTx1
(P0-P4)5x1GTx2
(P5-P9)
SCR
SCR
FlowStats1
SRAM1
SRAM2FlowStats2XScale XScale
NAT Pktreturn
SC
R
SRAMArchive Records
PortSplitter
QM0 SCR
QM1 SCR
QM2 SCR
QM3 SCR
Stats(1 ME) SRAM3SCR
SCR
SR
AM
Freelist
4 - Flow Stats Module – John DeHart and James Moscola
Overview of Flow Stats
Main functions»Uniquely identify flows based on 6-tuple
Hash header values to get an index into a table of records»Maintain packet and byte counts for each flow
Compare packet header with header values in record, and increment if same
Otherwise, follow hash chain until correct record is found»Send flow information to XScale for archiving every five minutes
Secondary functions»Maintain hash table
Identify and remove flows that are no longer active Invalid flows are removed so memory can be resused
5 - Flow Stats Module – John DeHart and James Moscola
Design Considerations
Efficiently maintaining a hash table with chained collisions»Efficiently inserting and deleting records
Efficiently reading hash table records
Synchronization issues»Multiple threads modifying hash table and chains
6 - Flow Stats Module – John DeHart and James Moscola
Start Timestamp (16b)
Packet Counter (32b)
SrcPort (16b) DestPort (16b)
Destination Address (32b)
Source Address (32b)
Protocol (8b)
LW0
LW1
LW2
LW3
LW4
LW5
LW6
LW7
Flow Record Total Record Size = 8 32-bit words
» V is valid bit Only needed at head of chain ‘1’ for valid record ‘0’ for invalid record
» Start timestamp (16-bits) is set when record starts counting flow
Reset to zero when record is archived» End timestamp (16-bits) is set each
time a packet is seen for the given flow
» Packet and Byte counters are incremented for each packet on the given flow
Reset to zero when record is archived» Next Record Number is next record in
hash chain 0x1FFFF if record is tail Address of next record =
(next_record_num * record_size) + collision_table_base_addr
Next Record Number (17b)
Slice ID (VLAN) (12b)Reserved
(6b)
Byte Counter (32b)
Reserved (14b)
= Member of 6-tuple
V(1b)
End Timestamp (16b)
TCP Flags(6b)
7 - Flow Stats Module – John DeHart and James Moscola
Timestamp Details Timestamp on XScale is 64-bits
Storing 64-bit start and end timestamps would cause each flow record to be too large for a single SRAM read
Instead, only store the 16-bits of each timestamp required to represent a five minute time interval» Clock frequency = 1.4 GHz» Timestamp increments every 16 clock cycles» Use bits 41:26 for 16 bit timestamps
(226 * 16 cycles)/1.4GHz = .767 seconds (241 * 16 cycles)/1.4GHz =25131.69 seconds (418 minutes)
» Time interval that can be represented using these bits .767 seconds through 418 minutes
8 - Flow Stats Module – John DeHart and James Moscola
Hash Table Memory Allocating 4 MBytes in SRAM Channel 3 for hash table
»Supports ~130K records»Divided memory 75% for the main table and 25% for
the collision table»Memory required =
Main_table_size + Collision_table_size.75*(#records * #bytes/record) + .25*(#records * #bytes/record)~98K records + ~32K records~3Mbytes + ~1Mbytes
Space for main table and collision table can be adjusted to tune performance»Larger main table means fewer collisions, but still need
adequate space for collision table CollisionTable
MainTable
~25%
~75%
9 - Flow Stats Module – John DeHart and James Moscola
Inserting Into Hash Table IXP has 3 different hash functions (48-bit, 64-bit, 128-bit)
» Using 64-bit hash function is sufficient and takes less time than 128-bit hash function
Not including Source Addr or Protocol into address HASH(D.Addr, S.Port, D.Port);
Result of hash is used to address the main hash table» Since we want ~100K records in main table, result of hash is used to get as
close to 100K entries as possible by adding a 16bit and 15bit chunk from the hash result
hash_result(15:0) + hash_result(30:16) = record_number» Records in the main table represent the head of a chain» If slot at head of chain is empty (valid_bit=0), store record there» If slot at head of chain is occupied, compare 6-tuple
If 6-tuple matches If packet_count == 0 then (existing flows will have 0 packet_counts when
previous packets on flow have just been archived)– Increment packet_counter for record– Add size of current packet to byte_counter– Set start and end time stamps
If packet_count > 0 then– Increment packet_counter for record– Add size of current packet to byte_counter– Set end time stamp
If 6-tuples doesn’t match then a collision has occurred and the record needs to be stored in collision table
CollisionTable
MainTable
10 - Flow Stats Module – John DeHart and James Moscola
Hash Collisions Hash collisions are chained in linked list
» Head of list is in the main table» Remainder of list is in collision table
SRAM ring maintains list of free slots in collision table» Slots are numbered from 0 to #_Collision_Table_Slots
Same as next_record_number To convert to memory address
(slot_num * record_size) + collision_table_base_addr» When a collision occurs, a pointer to an open slot in the
collision table can be retrieved from the SRAM ring» When a record is removed from the collision table, a pointer
is returned to the SRAM ring for the invalidated slotCollision
Table
MainTable
SRAMRing
Free list
11 - Flow Stats Module – John DeHart and James Moscola
Archiving Hash Table Records Send all valid records in hash table to
XScale for archiving every 5 minutes For each record in the main table (i.e. start
of chain) ...» For each record in hash chain ...
If record is valid ... If packet count > 0 then
– Send record to XScale via SRAM ring– Set packet count to 0– Set byte count to 0– Leave record in table
If packet count == 0 then– Flow has already been archived– No packet has arrived on flow in 5 minutes – Record is no longer valid– Delete record from hash table to free
memory
Start Timestamp_high (32b)
Start Timestamp_low (32b)
End Timestamp_high (32b)
Packet Counter (32b)
SrcPort (16b) DestPort (16b)
Destination Address (32b)
Source Address (32b)
Protocol (8b)
LW0
LW1
LW2
LW3
LW4
LW5
LW6
LW7
End Timestamp_low (32b)
LW8
LW9
Slice ID (VLAN) (12b)Reserved
(6b)
Byte Counter (32b)
Info Sent to XScale for eachflow every 5 minutes
TCP Flags(6b)
12 - Flow Stats Module – John DeHart and James Moscola
Deleting Records from Hash Table
While archiving records» If packet count is zero then remove record from
hash table Record has already been archived, and no packets have
arrived in the last five minutes
To remove a record» If ((record == head) && (record == tail))
Valid_bit = 0
»Else If ((record == head) && (record != tail)) Replace record with record.next Free the slot for the moved record
»Else if record != head Set previous records next pointer to record.next Free slot for the deleted record
CollisionTable
MainTable
SRAMRing
Free list
13 - Flow Stats Module – John DeHart and James Moscola
Memory Synchronization Issues Multiple threads reading/writing same block of memory
Only allow 1 ME to modify structure of hash table»Inserting and deleting nodes
Use global registers to indicate that the structure of the hash table is being modified»Eight global lock registers (1 per thread) to indicate what chain in
the hash table is being modified»When a thread wants to insert/delete a record from hash table
Store pointer to the head of the hash chain in the threads dedicated global lock register
If another thread is processing a packet that hashed to the same hash chain, wait for lock register to clear and restart processing packet
Otherwise, continue processing the packet normally Clear global lock register when done with insert/deletes
Value of 0xFFFFFFFF indicates that lock is clear
14 - Flow Stats Module – John DeHart and James Moscola
Flow Stats Execution ME 1
» Init - Configure hash function» 8 threads
Read packet header Hash packet header Send header and hash result to ME2 for processing
ME 2 (thread numbers may need adjusting)
» Init - Load SRAM ring with addresses for each slot in the collision tableInit - Set TIMESTAMP to 0
» 7 threads (ctx 1-7) Insert records into hash table Increment counter for records
» 1 thread (ctx 0) Archive and delete hash table records
15 - Flow Stats Module – John DeHart and James Moscola
Diagram of Flow Stats Execution (ME1)
get bufferhandle from QM
read bufferdescriptor (SRAM)
read packetheader (DRAM)
build hash key
compute hash
send packetinfo to ME2
send bufferhandle to TX
150 cycles
300 cycles
~50 cycles
100 cycles
60 cycles
60 cycles
60 cycles
~570 cycles
300 cycles
300 cycles
16 - Flow Stats Module – John DeHart and James Moscola
Incrementing Counters» Adds records to hash chain, but doesn’t remove them
match?valid?
read hash tablerecord (SRAM)
comparerecord to header
insertnew record
NoYes
Yes
No
~10 cycles
150 cycles
get packetinfo from ME1
60 cycles
tail?
Yes
No
get record slotfrom freelist
150 cycles
insertnew record
read nextrecord in chain
150 cycles
Best: ~360 cyclesWorst: ~520 +160x
x
Diagram of Flow Stats Execution (ME2)
Iterating through hash chainLocking head of chain
clear lockregister
count==0?
No
Yes
Write START/ENDtime & new counts
Write ENDtime & new counts
clear lockregister
clear lockregister
clear lockregister
set registerto lock chain
set registerto lock chain
set registerto lock chain
set registerto lock chain
150 cycles 150 cycles150 cycles150 cycles
17 - Flow Stats Module – John DeHart and James Moscola
read currenttime
set valid bitto zero
head of list?
No
write next_ptr toprevious list item
return recordslot to freelist
set registerto lock chain
clear lockregister
set registerto lock chain
clear lockregister
tail of list?Yes
set registerto lock chain
readrecord.next
replace recordwith record.next
return record.nextslot to freelist
clear lockregister
Diagram of Flow Stats Execution (ME2) Archiving Records
» Removes records from hash chain, but doesn’t add them» Processing of archiving records occurs every five minutes
5 minutes?No
Yesread next recordfrom main table
send recordto XScale
set registerto lock chain
reset countersand timestamps
clear lockregister
more recordsin chain?
count == 0?Yes
No
Yes
Waiting to archive
Locking head of chain
valid?
done withall records?
Yes
No
No
Yes
read next recordin chain
No
Yes
No
18 - Flow Stats Module – John DeHart and James Moscola
match currentchain?
Yes
check globallock values
No
continue processing packet
Return from Swap When returning from each CTX switch, always check global lock
registers» If any of the global locks contain the address of the hash chain that the current
thread is trying to modify, then the hash chain is locked and the current thread must restart processing on the current packet
» If none of the global locks contain the address of the hash chain that the current thread is trying to modify, then the current thread can just continue processing that packet as usual
restart procssingpacket
19 - Flow Stats Module – John DeHart and James Moscola
SPP V1 LC Egress with 1x10Gb/s Tx
FlowStats1NN
1x10GTx1
SRAM3FlowStats2XScale
SC
R
SRAMArchive Records
QM0
QM1
QM2
QM3
SCR
SR
AM
Freelist
SrcPort (16b) DestPort (16b)
Destination Address (32b)
Source Address (32b)
Slice ID (VLAN) (12b)
Protocol (8b)
Hash Result (17b)
Rsv(2b)
Rsvd (3b)
Packet Length (16b)
Start Timestamp_high (32b)
Start Timestamp_low (32b)
End Timestamp_high (32b)
Packet Counter (32b)
SrcPort (16b) DestPort (16b)
Destination Address (32b)
Source Address (32b)
Protocol (8b)
End Timestamp_low (32b)
Slice ID (VLAN) (12b)Reserved
(6b)
Byte Counter (32b)
Buffer Handle(24b)Rsv(3b)
Port(4b)
V1
V: Valid Bit
TCP Flags(6b)
TCP Flags(6b)
20 - Flow Stats Module – John DeHart and James Moscola
Flow Statistics Module Scratch rings
» QM_TO_FS_RING_1: 0x2400 – 0x27FF // for receiving from QM» QM_TO_FS_RING_2: 0x2800 – 0x2BFF // for receiving from QM» FS1_TO_FS2_RING: 0x2C00 - 0x2FFF // for sending data from FS1 to FS2» FS_TO_TX_RING_1: 0x3000 - 0x33FF // for sending data to TX1» FS_TO_TX_RING_2: 0x3400 – 0x37FF // for sending data to TX2
SRAM rings» FS2_FREELIST: 0x???? - 0x???? // stores list of open slots in collision table» FS2_TO_XSCALE: 0x???? – 0x???? // for sending record information to the XScale for archiving
LC Egress SRAM Channel 3 info for Flow Stats» HASH_CHAIN_TAIL 0x1FFFF // indicates the end of a hash chain» ARCHIVE_DELAY 0x0188 // 5 minutes
» RECORD_SIZE 8 * 4 = 32 // 8 32-bit words/record * 4 bytes/word» TOTAL_NUM_RECORDS 130688 // MAX with 4 MB table is ~130K records» NUM_HASH_TABLE_RECORDS 98304 // NUM_HASH_TABLE_RECORDS<=TOTAL_NUM_RECORDS (mod 32 = 0)» NUM_COLLISION_TABLE_RECORDS TOTAL_NUM_RECORDS - NUM_HASH_TABLE_RECORDS = 32384
» LCE_FS_HASH_TABLE_BASE SRAM_CHANNEL_3_BASE_ADDR + 0x200000 = 0xC0200000» LCE_FS_HASH_TABLE_SIZE 0x400000» LCE_FS_COLLISION_TABLE_BASE (HASH_TABLE_BASE + (RECORD_SIZE * NUM_HASH_TABLE_RECORDS)) = 0xC0500000
21 - Flow Stats Module – John DeHart and James Moscola
Overview of Flow Stats
2 MEs in Fastpath to collect flow data for each pkt»Byte counter per flow»Pkt counter per flow»Archive data to XScale via SRAM ring every 5 minutes
XScale control daemon(s) to process data»Receive flow information from MEs»Reformat to put into PlanetFlow format»Maintain databases for PlanetLab archiving and for identifying internal flows (pre-NAT translation) when an external flow (post-NAT) has a complaint lodged against it.
22 - Flow Stats Module – John DeHart and James Moscola
SPP V1 LC Egress with 10x1Gb/s Tx
SWITCH
MSF
Rx1
RBUF
Rx2Key
ExtractLookup
HdrFormat
MSF
TBUF
NNNN NN NN
RTM
NN
SC
R
XScale
NAT MissScratch Ring
TCAM
5x1GTx1
(P0-P4)5x1GTx2
(P5-P9)
SCR
SCR
FlowStats1
SRAM1
SRAM2FlowStats2XScale XScale
NAT Pktreturn
SC
R
SRAMArchive Records
PortSplitter
QM0 SCR
QM1 SCR
QM2 SCR
QM3 SCR
Stats(1 ME) SRAM3SCR
SCR
SR
AM
Freelist
23 - Flow Stats Module – John DeHart and James Moscola
Start Timestamp (16b)
Packet Counter (32b)
SrcPort (16b) DestPort (16b)
Destination Address (32b)
Source Address (32b)
Protocol (8b)
LW0
LW1
LW2
LW3
LW4
LW5
LW6
LW7
Flow Record Total Record Size = 8 32-bit words
» V is valid bit Only needed at head of chain ‘1’ for valid record ‘0’ for invalid record
» Start timestamp (16-bits) is set when record starts counting flow
Reset to zero when record is archived» End timestamp (16-bits) is set each
time a packet is seen for the given flow
» Packet and Byte counters are incremented for each packet on the given flow
Reset to zero when record is archived» For TCP Flows, the TCP Flags are or’ed
in from each packet» Next Record Number is next record in
hash chain 0x1FFFF if record is tail Address of next record =
(next_record_num * record_size) + collision_table_base_addr
Next Record Number (17b)
Slice ID (VLAN) (12b)Reserved
(6b)
Byte Counter (32b)
Reserved(14b)
= Member of 6-tuple
V(1b)
End Timestamp (16b)
TCP Flags(6b)
24 - Flow Stats Module – John DeHart and James Moscola
Archiving Hash Table Records Send all valid records in hash table to
XScale for archiving every 5 minutes For each record in the main table (i.e. start
of chain) ...» For each record in hash chain ...
If record is valid ... If packet count > 0 then
– Send record to XScale via SRAM ring– Set packet count to 0– Set byte count to 0– Leave record in table
If packet count == 0 then– Flow has already been archived– No packet has arrived on flow in 5 minutes – Record is no longer valid– Delete record from hash table to free
memory
Start Timestamp_high (32b)
Start Timestamp_low (32b)
End Timestamp_high (32b)
Packet Counter (32b)
SrcPort (16b) DestPort (16b)
Destination Address (32b)
Source Address (32b)
Protocol (8b)
LW0
LW1
LW2
LW3
LW4
LW5
LW6
LW7
End Timestamp_low (32b)
LW8
LW9
Slice ID (VLAN) (12b)Reserved
(6b)
Byte Counter (32b)
Info Sent to XScale for eachflow every 5 minutes
TCP Flags(6b)
25 - Flow Stats Module – John DeHart and James Moscola
Overview of Flow Stats Control
Main functions»Collection of Flow Information for PlanetLab Node
Used when a complaint is lodged about a misbehaving flow Must be able to identify flow and the Slice that produced it.
»Aggregation of Flow Information from: Multiple GPEs Multiple NPEs
»Correlation with NAT records to identify internal flow and external flow
External flow will be what complaint will be about. Internal flow will be what involved PlanetLab researcher will
know about.
26 - Flow Stats Module – John DeHart and James Moscola
Overview of PlanetFlow PlanetFlow
»Unprivileged slice Flow Collector:
Ulogd (fprobe-ulog)– Netlink socket– Uses VSys for
privileged operations– Every 5 minutes
dumps its cache to DB DB:
On PlanetLab Node 5-minute records Flows spanning 5-minute
intervals aggregated daily.
Central Archive»At Princeton?»Updated periodically by
using rsync to retrieve new DB entries from ALL PlanetLab nodes.
27 - Flow Stats Module – John DeHart and James Moscola
SPP PlanetFlow
IngressXScale
EgressXScale
MEsS
CR
SR
AM
SC
R
SCD
NATScratchRings
FlowStatsSRAMRing
CP
ExtPFDB
NATd FSd
NATrecords
Flowrecords
GPEPFDB
GPE
dbAccumulator
CentralArchive
rsync
PFDB
HF LK FS2Central Archive Record = <time, sliceID, Proto, SrcIP, SrcPort, DstIP, DstPort, PktCnt, ByteCnt>Ext PF DB Record = <Central Archive Record>
28 - Flow Stats Module – John DeHart and James Moscola
SPP PlanetFlow
IngressXScale
EgressXScale
MEsS
CR
SR
AM
SC
R
SCD
NATScratchRings
FlowStatsSRAMRing
CP
ExtPFDB
NATd FSd
NATrecords
Flowrecords
GPEPFDB
GPE
dbAccumulator
CentralArchive
rsync
PFDB
HF LK FS2Central Archive Record = <time, sliceID, Proto, SrcIP, SrcPort, DstIP, DstPort, PktCnt, ByteCnt>Ext PF DB Record = <Central Archive Record>
29 - Flow Stats Module – John DeHart and James Moscola
Translations needed
NPE Flow Records:»VLAN to SliceID
Comes from SRM»IXP timestamp to wall clock time
SCD records wall clock time it started IXP How do we manage time slip between clocks?
GPE Flow Records:»NAT Port translations
Src Port from GPE record becomes SPP Orig Src Port Src Port from natd translation record becomes Src Port
natd provides port translation updates
30 - Flow Stats Module – John DeHart and James Moscola
SPP PlanetFlow Databases
NATrecords
Flowrecords
CentralArchive
ExtPFDB
CP
CP
CP
PFDB
GPE
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, proto, srcIP, intSrcPort, xlatedSrcPort>
31 - Flow Stats Module – John DeHart and James Moscola
Merging of DBs NPE Flows
»No NAT»Goes directly into Ext PF DB
SPP Orig Src Port == SrcPort
»Do they need SliceID translation? We use the VLAN, but this probably needs to be the PlanetLab version of a
Slice ID. SRM will provide a VLAN to SliceID translation
Where and When?
GPE Configured Flows»No NAT»Goes directly into Ext PF DB
SPP Orig Src Port == SrcPort GPE NAT Flows
»Find corresponding NAT Record, extract Translated SrcPort Insert record into Ext PF DB with original SrcPort moved to SPP Orig Src Port Set Src Port to translated SrcPort
CP Traffic?
32 - Flow Stats Module – John DeHart and James Moscola
Overview of PlanetFlow PlanetFlow
»Unprivileged slice Flow Collector:
Ulogd (fprobe-ulog)– Netlink socket– Uses VSys for
privileged operations– Every 5 minutes
dumps its cache to DB DB:
On PlanetLab Node 5-minute records Flows spanning 5-minute
intervals aggregated daily.
Central Archive»At Princeton?»Updated periodically by
using rsync to retrieve new DB entries from ALL PlanetLab nodes.
X X
33 - Flow Stats Module – John DeHart and James Moscola
PlanetFlow Raw Data0005 0011 8e10638b 48a40477 00062638
0000371d 0000 0000 80fc99cd 80fc99d3
00000000 0000 0004 0000000b 0000062d
8dae5570 8dae558b cc1f 01bb 00 1f 0600
0000 0000 02000000 80fc99cd 80fc99d3
00000000 0000 0004 0000001a 000008b7
8dae54eb 8dae5533 cc1e 01bb 001e 0600
0000 0000 02000000
SA DA
IPv4 NextHop(Unused) Pkt Count Byte Count
Src Port Dst Port Pad
Tcpflag
sProto
Src
Tos
Src As(Unused)
Dst As(Unused) XID (SliceID) SA DA
In SNMP(if_nametoindex)
Out SNMP(if_nametoindex) Pkt Count Byte Count
First Switched(flow creation time)
Last Switched(time of last pkt) Src Port Dst Port Pa
d
Tcpflag
s
Src
Tos
XID (SliceID)
Uptime Unix Secs Unix nSecsVersion Count
Flow SequencePad16
(unused)
First Switched(flow creation time)
Last Switched(time of last pkt)
In SNMP(if_nametoindex)
Out SNMP(if_nametoindex)
IPv4 NextHop(Unused)
Src As(Unused)
Dst As(Unused)
NetFlow Header (beginning of file and repeats
every 30 flow records)
NetFlow FlowRecord
NetFlow FlowRecord
128.252.153.205128.252.153.211
52254 443
52255 443
128.252.153.205128.252.153.211
Proto
EngineType
(unused)
Engine Id
(unused)
223126
158111
34 - Flow Stats Module – John DeHart and James Moscola
SPP/PlanetFlow Raw Data0005 0011 8e10638b 48a40477 00062638
0000371d xx yy 0000 80fc99cd 80fc99d3
00000000 0000 0004 0000000b 0000062d
8dae5570 8dae558b cc1f 01bb 00 1f 0600
zzzz 0000 02000000 80fc99cd 80fc99d3
00000000 0000 0004 0000001a 000008b7
8dae54eb 8dae5533 cc1e 01bb 001e 0600
zzzz 0000 02000000
SA DA
IPv4 NextHop(Unused) Pkt Count Byte Count
Src Port Dst Port Pad
Tcpflag
sProto
Src
Tos
SPP OrigSrc Port
Dst As(Unused) XID (SliceID) SA DA
In SNMP(if_nametoindex)
Out SNMP(if_nametoindex) Pkt Count Byte Count
First Switched(flow creation time)
Last Switched(time of last pkt) Src Port Dst Port Pa
d
Tcpflag
s
Src
Tos
XID (SliceID)
Uptime (msecs) Unix Secs Unix nSecsVersion Count
Flow SequencePad16
(unused)
First Switched(msec)(flow creation time)
Last Switched(msec)(time of last pkt)
In SNMP(if_nametoindex)
Out SNMP(if_nametoindex)
IPv4 NextHop(Unused)
SPP OrigSrc Port
Dst As(Unused)
NetFlow Header (beginning of file and repeats
every 30 flow records)
NetFlow FlowRecord
NetFlow FlowRecord
128.252.153.205128.252.153.211
52254 443
52255 443
128.252.153.205128.252.153.211
Proto
SPPEngineType
SPPEngine
Id
223126
158111
35 - Flow Stats Module – John DeHart and James Moscola
Issues and Notes Time:
» Keeping time in sync among various machines: Flow Stats ME timestamps with IXP clock ticks.
Something has to convert this to a Unix time. GPE(s) timestamps with Unix gettimeofday(). CP collects flow records and aggregates based on time. Proposal:
XScale, GPE(s) and CP will use ntp to keep their Unix times in sync At the beginning of each reporting cycle, the Flow Stats ME should send a timestamp
record just to allow the XScale and CP to keep the time in sync. OR: Can XScale read the IXP clock tick and report that to the CP with along with the
XScale’s Unix time.» What are the times that are recorded in the Header and Flow Records?
Header Uptime (msecs): msecs since a base start time Time since Unix Epoch: time since January 1, 1970
– Unix secs– Unix nSecs
Uptime and Unix (secs, nSecs) represent the SAME time– So that the Flow times can be calculated based on them.
Flow Record First Switched (flow creation time): msecs since a base start time Last Switched (last packet in flow seen time): msecs since base start time
36 - Flow Stats Module – John DeHart and James Moscola
Issues and Notes (continued) NetFlow Header
» Filled in AFTER 30 flow records are filled in OR we get a timeout (10 minutes)» COUNT field tells how many flow records are valid.
File or data packet is ALWAYS padded out to a size that would hold 30 flow records» Flow Sequence: Running total of number of flow records emitted.
Flow Header and Flow Records» Emitted in chunks of 30 flow records plus a Flow Header
Emitted either by writing to a file or sending over a socket to a mirror site. Padded out to a size that would hold 30 flow records.
» A flow is emitted when it has been inactive for at least a minute or when it has been active for at least 5 minutes.
Fprobe-ulog threads:» emit_thread» scan_thread» cap_thread» unpending_thread
Flow lists» flows[]: hashed array of flows, buckets chained off head of list
These are flows that have been reported over netlink socket» flows_emit: linked list of flows ready to be emitted.
37 - Flow Stats Module – John DeHart and James Moscola
Issues and Notes (continued) VLANs and SliceIDs
» NPE and LC use VLANs to differentiate Slices» Flow records must record slice IDs
SRM will provide VLAN to SliceID translation
» GPE(s) do not differentiate Slices by VLAN. All flows from a GPE will use the same VLAN GPE keeps flow records locally using Slice ID Flow Stats ME could ignore GPE flow packets if it was told what the default GPE VLAN
was. Otherwise, one of the fs daemons could drop the flow records for the GPE flows that the Flow Stats
ME reports.
Slice ID:» What exactly is it?» Is the XID that is recorded by PlanetFlow actually the slice id or is it the VServer id?
38 - Flow Stats Module – John DeHart and James Moscola
Issues and Notes (continued) NAT Port Translations
» GPE flow records are the ones that need the NAT Port translation data» GPE flow records will come across from the GPE(s) to the CP via rsync or similar» natd will report NAT port translations with timestamps to the fs daemon» fs daemon will have to maintain NAT port translations (with their timestamps)
for possible later correlation with GPE flow records GPE(s) will all use the same default VLAN
» SRM will send this VLAN to scd so it can write it to SRAM for the fs ME to read in Fs ME will then filter out GPE flow records.
SRM fsd messaging» srm will push out VLAN SliceID translation creation and deletion messages
srm will wait ~10 minutes before re-using a VLAN srm will send the delete VLAN message after waiting the 10 minutes. fsd should not have to keep any history of VLAN/SliceID translations
It should get the creation before it receives any flow records for it It should get the last flow record before it gets the deleteion
» fsd will also be able to query SRM for current translation This will facilitate a restart of the fsd while the SRM maintains current state.
39 - Flow Stats Module – John DeHart and James Moscola
Issues and Notes (continued) rsync of flow record files from GPE(s) to CP
» A particular run of rsync may get a file that is still being written to by fprobe-ulog on the GPE
A subsequent rsync will may get the file again with additional records in it.
» Sample rsync command: rsync --timeout 15 -avzu -e "ssh -i /vservers/plc1/etc/planetlab/root_ssh_key.rsa " root@drn02:/vservers/pl_netflow/pf /root/pf
This will report the files that have been copied over
40 - Flow Stats Module – John DeHart and James Moscola
Issues and Notes (continued) Sample fprobe-ulog command:
» /sbin/fprobe-ulog -M -e 3600 -d 3600 -E 60 -T 168 -f pf2 -q 1000 -s 30 -D 250000» Started from /etc/rc.d/rc[2345].d/S56fprobe-ulog
All linked to /etc/init.d/fprobe-ulog GPE Flow record collection daemon: fprobe-ulog
» Scan thread Collects flow records into a linked list
» Emit thread Periodically writes flow records out to a file
Every 600 seconds – ten minutes!
» Daemon can also send flow records to a remote collector! So we could have the GPEs emit their flow records directly to the flow stats daemon on
the CP. Sample command:
/sbin/fprobe-ulog -M -e 3600 -d 3600 -E 60 -T 168 -f pf2 -q 1000 -s 30 -D 250000 <remote>:<port>[/[<local][/<type]] … There can be multiple remote host specifications Where
– remote: remote host to send to– port: destination port to send to– local: local hostname to use– type: m for mirror-site, r for rotate-site– send to all mirror-sites, rotate through rotate-sites.
41 - Flow Stats Module – John DeHart and James Moscola
SPP PlanetFlow
IngressXScale
EgressXScale
MEsS
CR
SR
AM
SC
R
scd
NATScratchRings
FlowStatsSRAMRing
CP
ExtPFDB
natd
fsd
GPE
GPE
CentralArchive
rsync
HF LK FS2Central Archive Record = <time, sliceID, Proto, SrcIP, SrcPort, DstIP, DstPort, PktCnt, ByteCnt>Ext PF DB Record = <Central Archive Record>
fprobe
fprobesrm
42 - Flow Stats Module – John DeHart and James Moscola
Plan/Design Flow Stats daemon, fsd, runs on CP
»Collects flow records from GPE(s) and NPE(s) and writes them into a series of PlanetFlow2 files with names:
pf2.#, where # is (0-162) Current file is closed after N minutes and # is incremented and new file is
opened and started. This mimics what fprobe-ulog does now on the GPE(s)
These files are then collected periodically by PLC for use and archiving I don’t think there is any explicit indication that PLC has picked up the files but the
timing must be such that we know it is done before we roll over the file names and overwrite an old file.
»Gets NAT data from natd Keep records of this with timestamps so we can correlate with flow records
coming from GPE(s) Check with Mart on how this will work
»Gets VLAN to sliceID data from srm srm will send start translation, stop translation msgs with a 10 minute wait
period when stopping a translation to make sure we are done with flow records for that slice
FS ME archives records every 5 minutes. Slices are long lived (right?) so this should not be a problem Fsd can also request a translation from srm
This is in case fsd has to be restarted while srm and other daemons continue running.
43 - Flow Stats Module – John DeHart and James Moscola
Plan/Design (continued) Fsd gathers records from GPE(s) and NPE(s)
»Gathers flow records from GPE(s) via socket(s) from fprobe-ulog on GPE(s)
Come across as one data packet with up to 30 flow records Packet is padded out to full 30 flow records with Count in Header
indicating how many of them are valid Update NetFlow header to indicate that this is an SPP and which SPP
node it is using Engine Type and Engine ID fields Update with NAT data and write immediately out to current pf2 file
keeping its NetFlow header.»Gathers flow records from NPE(s) via socket from scd on XScale
Come across one flow record at a time No NetFlow Header
Create NetFlow Header With appropriate Uptime and UnixTime (secs, nsecs) With SPP Engine Type and SPP Engine ID Modify Flow Record times to be msecs correlated with Uptime
Update NPE flow record with SliceID from srm. Collect NPE records for a period of time or until we get 30 and then
write them out to current pf2 file with NetFlow header.
44 - Flow Stats Module – John DeHart and James Moscola
Plan/Design (continued)FS ME and scd
»Use a command field in records coming across from FS ME to scd
»Use one command to set current time When FS ME is starting an archive cycle, first it sends a
timestamp command When scd gets this timestamp command it associates it with
a gettimeofday() time and sends the FS ME time and the gettimeofday() time to the fsd on the CP so it can associated ME times with Unix times.
»Use another command to indicate flow records Flow records can be sent directly on to fsd on CP
45 - Flow Stats Module – John DeHart and James Moscola
End
46 - Flow Stats Module – John DeHart and James Moscola
OLD STUFF
47 - Flow Stats Module – John DeHart and James Moscola
PlanetFlow Raw Data0500 0b00 8385 1bd2 a148 31d4 0f00 f84d
0000 8134 0000 0000 fc80 cd99 bb42 04e0
0000 0000 0000 0400 0000 0500 0000 7c01
2e85 eeb2 6d85 d636 7b00 7b00 0000 0011
0000 0000 0002 0000 fc80 cd99 fc80 d399
0000 0000 0000 0400 0000 1a00 0000 b708
3785 9d52 3785 e352 b1b2 bb01 1e00 0006
0000 0000 0002 0000
SA DA
IPv4 NextHop(Unused) Pkt Count Byte Count
Src Port Dst Port Pad
Tcpflag
sProto
Src
Tos
Src As(Unused)
Dst As(Unused) XID (SliceID) SA DA
In SNMP(if_nametoindex)
Out SNMP(if_nametoindex) Pkt Count Byte Count
First Switched(flow creation time)
Last Switched(time of last pkt) Src Port Dst Port Pa
d
Tcpflag
sProto
Src
Tos
XID (SliceID)
Uptime Unix Secs Unix nSecsVersion Count
Flow SequenceEng. Type
(unused)
Engine Id
(unused)
Pad16(unused)
NetFlow Header (beginning of file and repeats
every 30 flow records)
NetFlow FlowRecord
NetFlow FlowRecord
Each 16 bits has bytes swapped
First Switched(flow creation time)
Last Switched(time of last pkt)
In SNMP(if_nametoindex)
Out SNMP(if_nametoindex)
IPv4 NextHop(Unused)
Src As(Unused)
Dst As(Unused)
48 - Flow Stats Module – John DeHart and James Moscola
SPP PlanetFlow Databases
NATrecords
Flowrecords
CentralArchive
ExtPFDB
CP
IntPFDB
CP
CP
CP
PFDB
GPE
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt, PE ID, intSrcPort>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, sliceID, proto, srcIP, srcPort, dstIP, dstPort, pktCnt, byteCnt>
<time, proto, srcIP, intSrcPort, xlatedSrcPort>
49 - Flow Stats Module – John DeHart and James Moscola
SPP PlanetFlow
IngressXScale
EgressXScale
MEsS
CR
SR
AM
SC
R
SCD
NATScratchRings
FlowStatsSRAMRing
CP
ExtPFDB
NATd FSd
NATrecords
Flowrecords
GPEPFDB
GPE
dbAccumulator
CentralArchive
rsync
PFDB
HF LK FS2Central Archive Record = <time, sliceID, Proto, SrcIP, SrcPort, DstIP, DstPort, PktCnt, ByteCnt>Ext PF DB Record = <Central Archive Record>Int PF DB Record = <Central Archive Record, NPE/GPE ID, Internal Src Port>
IntPFDB
50 - Flow Stats Module – John DeHart and James Moscola
Merging of DBs NPE Flows
»No NAT»Goes directly into Ext PF DB and into Int PF DB
Internal SrcPort == SrcPort
»Do they need SliceID translation? We use the VLAN, but this probably needs to be the PlanetLab version of a
Slice ID. SRM will provide a VLAN to SliceID translation
Where and When?
GPE Configured Flows»No NAT»Goes directly into Ext PF DB and into Int PF DB
Internal SrcPort == SrcPort GPE NAT Flows
»Find corresponding NAT Record, extract Translated SrcPort» Insert record with translated SrcPort into Ext PF DB» Insert record with internal SrcPort into Int PF DB
CP Traffic?