HP StorageWorks Fabric OS 6.1.1 administrator guide (5697-0235, December 2009)

Fabric OS 6.1.x administrator guide 387
FCIP services license
Most of the FCIP extension services described in this chapter require the High Performance Extension over
FCIP/FC license. Use the licenseShow command to verify the license is present on the hardware used
on both ends the FCIP tunnel. For details on obtaining and installing licensed features, see ”Licensed
features” on page 34.
Platforms that support SAN extension over IP
Fabric OS supports SAN extension between 400 Multi-protocol Routers or between FR4-18i blades
installed on 4/256 SAN Directors or DC SAN Backbone Directors. The 400 Multi-protocol Router and
FR4-18i both have16 physical Fibre Channel ports and two physical GbE ports.
NOTE: The FCIP Tunneling Service for the 400 Multi-protocol Router and FR4-18i blade is not
compatible with the XPath FCIP service; nor is it compatible with any other vendor’s FCIP
implementation.
QoS concepts and implementation over FCIP
Quality of Service (QoS) refers to policies for handling differences in data traffic. These policies are based
on data characteristics and delivery requirements. For example, ordinary data traffic is tolerant of delays
and dropped packets, but voice and video data are not. QoS policies provide a framework for
accommodating these differences in data as it passes through a network.
FOS versions 6.0.0 and later provide for Fibre Channel QoS through internal QoS priorities. Those
priorities can be mapped to TCP/IP network priorities. There are two options for TCP/IP network based
QoS:
• Layer three DiffServ code Points (DSCP).
• VLAN tagging and Layer two class of service (L2CoS).
DSCP quality of service
Layer three class of service DiffServ Code Points (DSCP) refers to a specific implementation for establishing
QoS policies as defined by RFC2475. DSCP uses six bits of the Type of Service (TOS) field in the IP header
to establish up to 64 different values to associate with data traffic priority.
DSCP settings are useful only if IP routers are configured to enforce QoS policies uniformly within the
network. IP routers use the DSCP value as an index into a Per Hop Behavior (PHB) table. Control
connections and data connections may be configured with different DSCP values. Before configuring DSCP
settings, determine if the IP network you are using implements PHB, and consult with the network
administrator to determine the appropriate DSCP values.
L2CoS quality of service
Devices in physical LANs are constrained by LAN boundaries. They are usually in close proximity to each
other, and share the same broadcast/multicast domain. Physical LANs often contain devices and
applications that have no logical relationship. Also, when logically related devices and applications reside
in separate LAN domains, they must be routed from one domain to the other.
A VLAN is a virtual LAN network. A VLAN may reside within a single physical network, or it may span
several physical networks. Related devices and applications that are separated by physical LAN
boundaries can reside in the same VLAN. Also, a large physical network can be broken down into smaller
VLANs. VLAN traffic is routed using 802.1Q compliant tags within an Ethernet frame. The tag includes a
unique VLAN ID, and Class of Service (CoS) priority bits. The CoS priority scheme (sometimes called Layer
two Class of Service, or L2CoS), uses only the upper three bits of the TOS field, allowing eight priorities.