• SonicOSX 7 Profile Objects
• Endpoint Security
• Bandwidth
  • Understanding Bandwidth Profiles
  • Bandwidth Profiles
    • Configuring Bandwidth Object Settings
      • Elemental Bandwidth Object Settings
    • Configuring BWM on an Interface
    • Configuring BWM in a Security Rule Action
    • Editing Bandwidth Profiles
    • Deleting Bandwidth Profiles
• Block Page
  • Customizing Block Page Settings
  • Cloning Block Pages
  • Deleting Block Pages
• Log and Alerts
  • Adding Log and Alerts Profiles
    • About Event Profiles
  • Editing Log and Alert Profiles
  • Deleting Log and Alert Profiles
• Intrusion Prevention
  • Configuring Intrusion Prevention Profiles
  • Deleting Intrusion Prevention Profiles
• QoS Marking
  • Classification
  • Marking
  • Conditioning
    • Site to Site VPN over QoS Capable Networks
    • Site to Site VPN over Public Networks
  • 802.1p and DSCP QoS
    • Enabling 802.1p
    • DSCP Marking
      • DSCP Marking and Mixed VPN Traffic
      • Configure for 802.1p CoS 4 – Controlled Load
      • QoS Mapping
      • Managing QoS Marking
  • Configuring QoS Marking
• DHCP Option
  • Configuring DHCP Option Objects
    • RFC-Defined DHCPV4 Option Numbers
    • RFC-Defined DHCPV6 Option Numbers
  • Editing DHCP Option Objects
  • Deleting DHCP Option Objects
• AWS
  • AWS Objects
    • About Address Object Mapping with AWS
    • Viewing Instance Properties in SonicOSX
    • Creating a New Address Object Mapping
    • Enable Mapping
    • Configuring Synchronization
    • Configuring Regions to Monitor
    • Verifying AWS Address Objects and Groups
• SonicWall Support
  • About This Document

Marking

After the traffic has been classified, if it is to be handled by QoS capable external systems (for example, CoS aware switches or routers as might be available on a premium service provider’s infrastructure, or on a private WAN), it must be tagged so that the external systems can make use of the classification, and provide the correct handling and Per Hop Behaviors (PHB).

Originally, this was attempted at the IP layer (layer 3) with RFC791’s three Precedence bits and RFC1394 ToS (type of service) field, but this was used by a grand total of 17 people throughout history. Its successor, RFC2474 introduced the much more practical and widely used DSCP (Differentiated Services Code Point) which offered up to 64 classifications, as well as user-definable classes. DSCP was further enhanced by RFC2598 (Expedited Forwarding, intended to provide leased-line behaviors) and RFC2697 (Assured Forwarding levels within classes, also known as Gold, Silver, and Bronze levels).

DSCP is a safe marking method for traffic that traverses public networks because there is no risk of incompatibility. At the very worst, a hop along the path might disregard or strip the DSCP tag, but it rarely mistreats or discard the packet.

The other prevalent method of CoS marking is IEEE 802.1P. 802.1P occurs at the MAC layer (layer 2) and is closely related to IEEE 802.1Q VLAN marking, sharing the same 16-bit field, although it is actually defined in the IEEE 802.1D standard. Unlike DSCP, 802.1P only works with 802.1p capable equipment, and is not universally interoperable. Additionally, 802.1P, because of its different packet structure, can rarely traverse wide-area networks, even private WANs. Nonetheless, 802.1p is gaining wide support among Voice and Video over IP vendors, so a solution for supporting 802.1P across network boundaries (such as WAN links) was introduced in the form of 802.1P to DSCP mapping.

802.1P to DSCP mapping allows 802.1P tags from one LAN to be mapped to DSCP values by SonicOS, allowing the packets to safely traverse WAN links. When the packets arrive on the other side of the WAN or VPN, the receiving SonicOS appliance can then map the DSCP tags back to 802.1P tags for use on that LAN. For more information, see 802.1p and DSCP QoS.