IBM eServer xSeries 135, Руководство пользователя

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IBM xSeries 135: User’s Reference
the primary Ethernet controller detects a link failure, all Ethernet traffic associated
with it is switched to the redundant (secondary) controller. This switching occurs
without any user intervention. When the primary link is restored to an operational
state, the Ethernet traffic switches back to the primary Ethernet controller.
High-performance Ethernet modes
Your Ethernet controllers support optional modes, such as teaming, priority packets,
and virtual LANs, which provide higher performance and throughput for your
server.
Teaming mode: Your Ethernet controllers provide options, called teaming options.
These options increase throughput and fault tolerance when running with Windows
NT
®
4.0 or NetWare 4.1x or later.
• Adapter fault tolerance (AFT) provides automatic redundancy for your adapter.
If the primary adapter fails, the secondary adapter takes over. Adapter fault
tolerance supports from two to four adapters per team.
• Adaptive load balancing (ALB) enables you to balance the transmission data
flow among two to four adapters. ALB also includes the AFT option. You can use
ALB with any 100BASE-TX switch.
• Cisco Fast EtherChannel (FEC) creates a team of 2 to 4 adapters to increase
transmission and reception thoughput. FEC also includes the AFT option. You
can use FEC only with a switch that has FEC capability.
Teaming requires you to install both integrated Ethernet controllers. For additional
information about the teaming options, refer to the documentation that comes with
these additional adapters.
Priority Packet mode: Priority Packet is a traffic-prioritization utility that enables
you to set up filters to process high-priority traffic before normal traffic. You can send
information from critical nodes or applications with an indicated priority. Because
you set this priority at the host or entry point of the network, the network devices can
base forwarding decisions on priority information defined in the packet.
Priority Packet information is available on the IBM Networking site at
http://www.ibm.com/networking/support on the World Wide Web.
Priority Packet prioritizes traffic based on priority filters. These are parameters that
you assign to outgoing (transmit) packets. Using the priority filter wizard, you can set
up predefined or custom priority filters based on a node (MAC) address, Ethernet
type, or by various properties of the protocol and port. Priority Packet provides two
different methods for prioritizing traffic: IEEE 802.1p tagging and High Priority
Queue.
IEEE 802.1p is an IEEE standard for tagging, or adding additional bytes of
information to packets with different priority levels. Packets are tagged with 4
additional bytes, which increase the packet size and indicate a priority level. When
you send these packets out on the network, the higher priority packets are transferred
first. Priority-packet tagging (also known as Traffic Class Expediting) enables the
adapter to work with other elements of the network (such as switches and routers) to
deliver priority packets first. You can assign specific priority levels from 0 (low) to 7
(high).
You can assign values to packets based on their priorities when you use the IEEE
802.1p standard for packet tagging. This method requires a network infrastructure
that supports packet tagging. The routing devices receiving and transferring these
packets on your network must support 802.1p for tagging to be effective.