User guide

9-24 E
XTREME
W
ARE
S
OFTWARE
U
SER
G
UIDE
Q
UALITY OF
S
ERVICE
(Q
O
S)
I
NTRA
-S
UBNET
Q
O
S
Intra-Subnet QoS
™
(ISQ) is used only on Extreme switches that do not use the “i”
chipset. Using ISQ, it is possible to apply Layer 3 and Layer 4 access lists to traffic that
is only being locally switched. Extreme products that use the “i” chipset are already
capable of using Layer 3 and Layer 4 access lists without enabling ISQ, even though the
switch is performing Layer 2 switching, only. The command syntax for all IP-related
access list commands is described in Chapter 16. ISQ is enabled on a per-VLAN basis.
Because ISQ instructs the switch to look at IP addresses within a VLAN, the normal
MAC-based learning and refreshing for Layer 2 switching is altered for traffic that
matches an IP-based traffic grouping. Instead, learning and refreshing is performed
based on IP information in the packets. As a result, the FDB aging timer is
automatically increased to a value comfortably above a normal ARP table refresh time;
to 50 minutes (3,000 seconds). ISQ should not be used on VLANs with clients that have
statically-defined ARP tables.
ISQ may also be used for the application of Layer 3 and Layer 4 QoS policies for traffic
on a switch that is destined outside the subnet served by the Layer 2-only switch. This
is a useful feature in conjunction with ExtremeWare Enterprise Manager (EEM) v2.0 or
above and the Dynamic Link Context System (DLCS) feature documented below. To
configure this capability, you need the MAC address of the next-hop router (or the
MAC address of the WINS server, if the server is on the same subnet), and the list of the
host IP addresses. The IP packets to this MAC address are then snooped.
ISQ commands are described in Ta bl e 9-1 3.
Table 9-13: ISQ Configuration Commands
Command Description
config isq-server <servers-listname> add
ipaddress <remote destination ipaddress1>
Adds a remote destination IP address.
config isq-server <servers-listname> add mac
<mac-address-of-next-hop> vlan <vlan
name>
Adds the MAC address of the next hop router.
config isq-server <servers-listname> delete
ipaddress <remote destination ipaddress1>
Deletes a remote destination IP address.
config isq-server <servers-listname> delete
mac <mac-address-of-next-hop> vlan <vlan
name>
Deletes the MAC address of the next hop router.