C
HAPTER
1
| Introduction
Description of Software Features
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IEEE 802.1Q
TUNNELING (QINQ)
This feature is designed for service providers carrying traffic for multiple
customers across their networks. QinQ tunneling is used to maintain
customer-specific VLAN and Layer 2 protocol configurations even when
different customers use the same internal VLAN IDs. This is accomplished
by inserting Service Provider VLAN (SPVLAN) tags into the customer’s
frames when they enter the service provider’s network, and then stripping
the tags when the frames leave the network.
TRAFFIC
PRIORITIZATION
This switch prioritizes each packet based on the required level of service,
using eight priority queues with strict priority, Weighted Round Robin
(WRR), or a combination of strict and weighted queuing. It uses IEEE
802.1p and 802.1Q tags to prioritize incoming traffic based on input from
the end-station application. These functions can
be used to provide
independent priorities for delay-sensitive data and best-effort data.
This switch also supports several common methods of prioritizing layer 3/4
traffic to meet application requirements. Traffic can be prioritized based on
the priority bits in the IP frame’s Type of Service (ToS) octet using DSCP, or
IP Precedence. When these services are enabled, the priorities are mapped
to a Class of Service value by the switch, and the traffic then sent to the
corresponding output queue.
QUALITY OF SERVICE Differentiated Services (DiffServ) provides policy-based management
mechanisms used for prioritizing network resources to meet the
requirements of specific traffic types on a per-hop basis. Each packet is
classified upon entry into the network based on access lists, IP Precedence
or DSCP values, or VLAN lists. Using access lists allows you select traffic
based on Layer 2, Layer 3, or Layer 4 information contained in each
packet. Based on network policies, different kinds of traffic can be marked
for different kinds of forwarding.
ETHERNET RING
PROTECTION
SWITCHING
ERPS can be used to increase the availability and robustness of Ethernet
rings, such as those used in Metropolitan Area Networks (MAN). ERPS
provides Layer 2 loop avoidance and fast reconvergence in Layer 2 ring
topologies, supporting up to 255 nodes in the ring structure. It can also
function with IEEE 802.1ag to support link monitoring when non-
participating devices exist within the Ethernet ring.
IP ROUTING The switch provides Layer 3 IP routing. To maintain a high rate of
throughput, the switch forwards all traffic passing within the same
segment, and routes only traffic that passes between different
subnetworks. The wire-speed routing provided by this switch lets you
easily link network segments or VLANs together without having to deal
with the bottlenecks or configuration hassles normally associated with
conventional routers.
Routing for unicast traffic is supported with static routing, and Routing
Information Protocol (RIP).
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