Quality of Service II ( Deployment, Design )

Quality of Service Deployment

Choosing the correct WAN Type.

• WAN Providers, you get what you pay for.
  • Tried and True providers
• Don’t design a sinking ship, bandwidth.
• Determine bursting capabilities.
• QoS classes / Policies support.
• Multicast support.

Modular QoS CLI ( MQC )

• Class-map

R1(config)#class-map ccdp
Class-map configuration commands:
  description  Class-Map description
  exit         Exit from class-map configuration mode
  match        classification criteria
  no           Negate or set default values of a command

R1(config-cmap)#mat
R1(config-cmap)#match ?
  access-group         Access group
  any                  Any packets
  atm                  Match on ATM info
  class-map            Class map
  cos                  IEEE 802.1Q/ISL class of service/user priority values
  destination-address  Destination address
  discard-class        Discard behavior identifier
  dscp                 Match DSCP in IPv4 and IPv6 packets
  fr-de                Match on Frame-relay DE bit
  fr-dlci              Match on fr-dlci
  group-object         Match object-group
  input-interface      Select an input interface to match
  ip                   IP specific values
  mpls                 Multi Protocol Label Switching specific values
  not                  Negate this match result
  packet               Layer 3 Packet length
  precedence           Match Precedence in IPv4 and IPv6 packets
  protocol             Protocol
  qos-group            Qos-group
  source-address       Source address
  vlan                 VLANs to match

• Policy-map

R1(config-pmap)#class ccdp
R1(config-pmap-c)#?
Policy-map class configuration commands:
  bandwidth        Bandwidth
  exit             Exit from QoS class action configuration mode
  fair-queue       Enable Flow-based Fair Queuing in this Class
  netflow-sampler  NetFlow action
  no               Negate or set default values of a command
  police           Police
  priority         Strict Scheduling Priority for this Class
  queue-limit      Queue Max Threshold for Tail Drop
  random-detect    Enable Random Early Detection as drop policy
  service-policy   Configure QoS Service Policy
  set              Set QoS values
  shape            Traffic Shaping

• Service-policy

AutoQoS Templates

• Automaticlly deploy ( QoS templates based on percentages )
  • R3(config-if)#auto discovery
  • R3(config-if)#auto qos voip [trust]

#CLASS-MAPS ARE CREATED
class-map match-any AutoQoS-VoIP-Remark
 match ip dscp ef
 match ip dscp cs3
 match ip dscp af31
class-map match-any AutoQoS-VoIP-Control-UnTrust
 match access-group name AutoQoS-VoIP-Control
class-map match-any AutoQoS-VoIP-RTP-UnTrust
 match protocol rtp audio
 match access-group name AutoQoS-VoIP-RTCP
!
!
#POLICY-MAPS ARE CREATED
policy-map AutoQoS-Policy-UnTrust
 class AutoQoS-VoIP-RTP-UnTrust
 priority percent 70
 set dscp ef
 class AutoQoS-VoIP-Control-UnTrust
 bandwidth percent 5
 set dscp af31
 class AutoQoS-VoIP-Remark
 set dscp default
 class class-default
 fair-queue

#ACL ARE CREATED
ip access-list extended AutoQoS-VoIP-Control
permit tcp any any eq 1720
permit tcp any any range 11000 11999
permit udp any any eq 2427
permit tcp any any eq 2428
permit tcp any any range 2000 2002
permit udp any any eq 1719
permit udp any any eq 5060
ip access-list extended AutoQoS-VoIP-RTCP
permit udp any any range 16384 32767

•  Requires CEF, no existing service-poilcy commands.
• Employs “Best of” practices; trust ( markings ) or no trust ( NBAR ).

Quality of Service Design

• Where to implement QoS?
  • Any point where congestion potential exists.
    • Aggregation points.
    • Rate Transitions.
  • Don’t soley trust on your monitoring.
  • Police your Agressive Tendancies.
• RFC4594 defines how to classify using the DiffServ Bits in the header
  • https://tools.ietf.org/html/rfc4594
• Cisco’s translation: 4-, 8-, and 12-class strategies

(c) cisco

• Start simple (4), grow as needed

    ------------------------------------------------------------------
   |   Service     |  DSCP   |    DSCP     |       Application        |
   |  Class Name   |  Name   |    Value    |        Examples          |
   |===============+=========+=============+==========================|
   |Network Control|  CS6    |   110000    | Network routing          |
   |---------------+---------+-------------+--------------------------|
   | Telephony     |   EF    |   101110    | IP Telephony bearer      |
   |---------------+---------+-------------+--------------------------|
   |  Signaling    |  CS5    |   101000    | IP Telephony signaling   |
   |---------------+---------+-------------+--------------------------|
   | Multimedia    |AF41,AF42|100010,100100|   H.323/V2 video         |
   | Conferencing  |  AF43   |   100110    |  conferencing (adaptive) |
   |---------------+---------+-------------+--------------------------|
   |  Real-Time    |  CS4    |   100000    | Video conferencing and   |
   |  Interactive  |         |             | Interactive gaming       |
   |---------------+---------+-------------+--------------------------|
   | Multimedia    |AF31,AF32|011010,011100| Streaming video and      |
   | Streaming     |  AF33   |   011110    |   audio on demand        |
   |---------------+---------+-------------+--------------------------|
   |Broadcast Video|  CS3    |   011000    |Broadcast TV & live events|
   |---------------+---------+-------------+--------------------------|
   | Low-Latency   |AF21,AF22|010010,010100|Client/server transactions|
   |   Data        |  AF23   |   010110    | Web-based ordering       |
   |---------------+---------+-------------+--------------------------|
   |     OAM       |  CS2    |   010000    |         OAM&P            |
   |---------------+---------+-------------+--------------------------|
   |High-Throughput|AF11,AF12|001010,001100|  Store and forward       |
   |    Data       |  AF13   |   001110    |     applications         |
   |---------------+---------+-------------+--------------------------|
   |    Standard   | DF (CS0)|   000000    | Undifferentiated         |
   |               |         |             | applications             |
   |---------------+---------+-------------+--------------------------|
   | Low-Priority  |  CS1    |   001000    | Any flow that has no BW  |
   |     Data      |         |             | assurance                |
    ------------------------------------------------------------------

                Figure 3. DSCP to Service Class Mapping<

How to monitor QoS?

• IP SLA.
• Verify carrier serivce agreements.
• Prove your network performance.
• Identify service issues before they’re an issue.