Quality of Service : an overview

3 787v structure

Thomson Gateways: Quite a bit of history in QOS

5 Release 4.1 > ATM QOS Categories: > Unspecified Bit Rate > Variable Bit Rate - non real-time > Constant Bit Rate ATM QOS categories ATM PVC shaping > Peak cell rate > Sustained Cell Rate > Maximum Burst Size Connection Admission Control

6 Release 4.2 > ATM QOS New Category: > Variable Bit Rate - real-time > ILMI 4.0 ATM Autoconfig (bridged connections only) > IPQOS: Label classification, based on : > Source : interface, interface group, address range, port > Destination : address range, port > Type of Service byte : DiffServ Code Point, Precedence > …… Label based forwarding

7 Release > IPQOS: AQM Queuing/ Scheduling > 4 queues with strict priority scheduling (residential products) > 6 queues strict priority / Weighted Fair Queueing (business) Tail drop or Early (BLUE) packet discard Propagation to lower priority queue Congestion shaping : prevent real-time queue to starve other queues Prioritize TCP ACK segments Default mapping of VLAN user priority to/from internal class

8 Release 5.3 > ATM QOS book revision > IPQOS Out-of-the-box DiffServ compliant Weighted Round Robin scheduling support TCP ACK optimization IP rate limiting (Meters) > per label/interface (mark/drop) > Re-marking of IP TOS byte : Precedence / DSCP Label classification extensions > Inheritance (using ALGs) > Bi-directional labels

9 Release 6. X > R6.1 Layer 2 QOS > Bridged scenarios > Classification : VLAN tag (p- bits) or IP TOS (precedence, DSCP) > No use of labels > R6.2 Application based labelling > System service manager configured QOS

10 Release 7.2 > Managed Ethernet Switch QOS Classification +Queuing > 4 queues > Real-time queue on BCM5335M only Ingress Rate Limiting Egress Rate Shaping Storm Control (=protection mechanism) > Ikanos CPE5 VDSL2 chipset QOS support Main topic of this presentation

11 Release 8.1 > Bridge classification with bridge filters > TG784 Ethernet WAN buffer dimensioning Ethernet path does not allow extensive support of QOS > Multi-link PPP (business)

Configuring QOS of the Ikanos CPE5

13 Introduction > How it works > How you configure it

14 How it works > Auto mode : Enable / Disable QOS depending on sync rate > Classification criteria P-bits in VLAN tag IP Precedence DSCP > Queueing : 4 queues Strict priority only

15 Auto mode > Below 10 Mbits/s sync rate : QOS enabled > Above 10 Mbits/s sync rate : QOS disabled > Threshold : configurable Default value = 10 Mbits/s (empirically determined value)

16 How you configure it > Configurable via CLI All Commands in group :xdsl qos {787v}[xdsl qos]=>? Following commands are available : config : qos configuration Following command groups are available : class queue {787v}[xdsl qos]=>

17 How you configure it > Configure general parameters > Classify : Map QOS information fields into Internal Class > Queue : Map Internal Classes into Queues

18 Configure general parameters > QOS Operational state : enabled / disabled > Auto mode > Auto mode threshold {787v}[xdsl qos]=>:xdsl qos config qos state: enable qos automode: enable qos autothreshold: 100(x100kps) {787v}[xdsl qos]=>

19 Map QOS info fields to Internal Class > CLI commands located in group :xdsl qos class > Determine which QOS information field to use : IPv4 TOS Byte : Precedence / DSCP value P-bits (EPrio) IPv4 TOS and EPrio are mutually exclusive :xdsl qos class config ethprio=enabled ipv4tos=disabled :xdsl qos class config ethprio=disabled ipv4tos=enabled > Map the QOS values to Internal class TOS byte :xdsl qos class ipv4tos add.... P-bits :xdsl qos class eprio config....

20 Map TOS byte : CLI details > Map TOS byte [0-255] to internal class [0-7] :xdsl qos class ipv4tos add tos=0 tosrangeend=143 class=0 > Check :xdsl qos class ipv4tos list IPv4 TOS to Class Map Tos 0 TosRangeEnd 143 class 0 Tos 144 TosRangeEnd 144 class 7 Tos 145 TosRangeEnd 183 class 0 Tos 184 TosRangeEnd 184 class 7 Tos 185 TosRangeEnd 255 class 0

21 Map P-bits : CLI details > Map P-bits [0-7] to internal class [0-7] :xdsl qos class eprio config prioclass > Check :xdsl qos class eprio list ethernet priority to class map pri[0] -> class 0 pri[1] -> class 0 pri[2] -> class 0 pri[3] -> class 0 pri[4] -> class 0 pri[5] -> class 0 pri[6] -> class 0 pri[7] -> class 0 These are the defaults

22 Map P-bits : example 1 > Map P-bits [0-7] to internal class [0-7] :xdsl qos class eprio config prioclass Maps p-bit : to class : > Check :xdsl qos class eprio list ethernet priority to class map pri[0] -> class 0 pri[1] -> class 1 pri[2] -> class 2 pri[3] -> class 3 pri[4] -> class 4 pri[5] -> class 5 pri[6] -> class 6 pri[7] -> class 7

23 Map P-bits : example 2 > Map P-bits [0-7] to internal class [0-7] :xdsl qos class eprio config prioclass Maps p-bit : to class : > Check :xdsl qos class eprio list ethernet priority to class map pri[0] -> class 7 pri[1] -> class 6 pri[2] -> class 5 pri[3] -> class 4 pri[4] -> class 3 pri[5] -> class 2 pri[6] -> class 1 pri[7] -> class 0

24 Map Internal Classes into Queues > CLI commands located in group :xdsl qos queue > Flow control is disabled in QOS Automode :xdsl qos queue number=(0-3) config flowcontrol=disabled > Map Internal Class to queue :xdsl qos queue map class=0 queue=0 drop=always > Verify with maplist :xdsl qos queue maplist

25 Example {787v}[xdsl qos queue]=>maplist xDSL qos queue map class queue rule 0 0 never 1 0 never 2 0 never 3 0 never 4 0 never 5 0 never 6 0 never 7 3 never

26 Thank you !