A QoS Case Study: Packet Marking

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A QoS Case StudyPacket Marking

• Chris Hose chose_at_stevens-tech.edu
• Alban Dani adani_at_stevens-tech.edu
• Jason Evans jevans_at_stevens-tech.edu

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COS (Ethernet Frame)

• COS Refers to three bits in the 802.1Q header
  that are used to indicate the priority of the
  Ethernet frame as it passes through a switched
  network.

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ToS (IP Packet)

• ToS is a one-byte field that exists in an IPV4
  header. The ToS field consists of eight bits, of
  which the first three bits are used to indicate
  the priority of the IP packet. These first three
  bits are referred to as the IP precedence bits.

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Topics

• Setting the checking QoS values in the campus
  network.
• Confirm endpoint is receiving QoS

Sending a receiving marked packets is only half
the story. Each switch and router that a
marked packet traverses must have multiple queues
to actually give priority to the packet.
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(No Transcript)
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Campus Network To NJEdge Extranet
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Test Setup

• Two Laptops
• with Microsoft NetMeeting
• USB Cameras
• QoS Drivers
• Ethereal Packet capture utility
• PolyCom units

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Add Driver to tag packets

• NetMeeting will automatically assign Class
  Selector values of 3 and 5 to video and voice
  respectively once the QoS Packet Scheduler
  Service is installed
• We will set the workgroup switch port to mark the
  packet with the proper value of 4

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NetMeeting Setup

• NetMeeting must be set at Cable, xDSL or ISDN
  or Local Area Network for the Polycom to answer
  the call.
• Campus Gatekeeper configuration

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CATA1 (2950-48)

• class-map match-all videoclass
• match access-group name VideoSrc
• policy-map videopolicy
• class videoclass
• police 5000000 8192 exceed-action drop
• set ip dscp 32
• interface FastEthernet0/40
• service-policy input videopolicy

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35xxXL

• For NetMeeting set all packets from port to CoS 4
• interface FastEthernet0/14
• switchport priority default 4
• For PolyCom the switch can trust the CoS value
• 35xx switches will trust CoS values by default,
  non video device ports should be set not to trust
  this marking.

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CatCore (6509 native IOS)

• mls qos
• interface GigabitEthernet7/7
• description All video device ports
• mls qos trust cos
• interface GigabitEthernet7/5
• description Connection to Pix (Vlan 7)
• mls qos trust dscp

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PIX

• See Frank Aversas presentation
• Stevens does not use NAT
• Configured the firewall to pass all packets to
  the endpoint without a problem

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Gatekeeper Endpoint Registration
stevensgk.ccsh gatekeeper endpoints
GATEKEEPER ENDPOINT REGISTRATION
CallSig
nalAddr Port RASSignalAddr Port Zone Name
Type Flags --------------- ----- ---------------
----- --------- ---- ----- 155.246.18.8 1720
155.246.18.8 1719 stevensgk TERM
H323-ID Stevens E164-ID 0012012165001 155.24
6.154.237 1720 155.246.154.237 1620 stevensgk
TERM H323-ID adani E164-ID
0012012168238 Total number of active
registrations 2
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Gatekeeper Call Status
stevensgk.ccsh gatekeeper calls Total number of
active calls 1.
GATEKEEPER CALL INFO
LocalCallID
Age(secs) BW 112-11283
52 256(Kbps) Endpt(s) Alias
E.164Addr src EP adani
0012012168238 CallSignalAddr Port
RASSignalAddr Port 155.246.154.237
1720 155.246.154.237 1632 Endpt(s) Alias
E.164Addr dst EP adani
0012012165001 CallSignalAddr Port
RASSignalAddr Port 155.246.154.237
1720 155.246.154.237 1632
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Test Point 3A
Test Point 1
to

• Select a packet from the far end endpoint under
  test

• Confirm the packet is marked

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Test Point 5
Test Point 1
to

• Select a packet from the far end endpoint under
  test

• Confirm the packet is marked

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Summary

• Mark packets as close to user as possible
• Trust CoS as opposed to DSCP when using 3500XL or
  2900XL
• Deploy 2950/3550 switches in areas which need QoS
  if possible
• We are trusting that only the proper traffic from
  other NJEdge institutions have QoS marked
• IOS version, IOS version, IOS version
• Marking Packets is only half the story, queuing
  is the other half