Edge-Core ECS4110-28T, Руководство по управлению, Страница: 80 / 1514

C
HAPTER
1
| Introduction
Description of Software Features
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IEEE 802.1Q
T
UNNELING
(Q
IN
Q)
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.
T
RAFFIC
P
RIORITIZATION
This switch prioritizes each packet based on the required level of service,
using four priority queues with strict priority, Weighted Round Robin (WRR)
scheduling, 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.
IP R
OUTING
The switch provides Layer 3 IP static 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.
Static Routing – Traffic is automatically routed between any IP interfaces
configured on the switch. Routing to statically configured hosts or subnet
addresses is provided based on next-hop entries specified in the static
routing table.
A
DDRESS
R
ESOLUTION
P
ROTOCOL
The switch uses ARP and Proxy ARP to convert between IP addresses and
MAC (hardware) addresses. This switch supports conventional ARP, which
locates the MAC address corresponding to a given IP address. This allows
the switch to use IP addresses for routing decisions and the corresponding
MAC addresses to forward packets from one hop to the next. Either static
or dynamic entries can be configured in the ARP cache.
Proxy ARP allows hosts that do not support routing to determine the MAC
address of a device on another network or subnet. When a host sends an
ARP request for a remote network, the switch checks to see if it has the
best route. If it does, it sends its own MAC address to the host. The host
then sends traffic for the remote destination via the switch, which uses its
own routing table to reach the destination on the other network.