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Defining Static Filters
Defining Type of Service filters
MAX 6000/3000 Network Configuration Guide 15-21
Examples of defining a TOS filter
The following examples define a TOS filter for TCP packets (protocol 6) that are destined for a
single host at 10.168.6.24. The packets must be sent on TCP port 23. For incoming packets that
match this filter, the priority is set at level 2. This relatively low priority, means that an
upstream router that implements priority queuing may can these packets when it becomes
loaded. The parameters also set TOS to prefer a low latency connection which means that the
upstream router will choose a fast connection if one is available, even if it is higher cost, lower
bandwidth, or less reliable than another available link.
srcport cmp
value
If the
srcport keyword is followed by a comparison symbol and
a port, the port is compared to the source port of a packet. The
comparison symbol can be < (less-than), = (equal), > (greater-than),
or ! = (not-equal). The port value can be one of the following names
or numbers: ftp-data (20), ftp (21), telnet (23), smtp (25),
nameserver (42), domain (53), tftp (69), gopher (70), finger (79),
www (80), kerberos (88), hostname (101), nntp (119), ntp (123),
exec (512), login (513), cmd (514), or talk (517). For more details,
see “Filtering by port numbers” on page 15-14.
precedence value Specifies the priority level of the data stream. The three most
significant bits of the TOS byte are priority bits used to set
precedence for priority queuing. If a packet matches the filter, the
bits are set to the specified value (most significant bit first). One of
the following values can be specified:
000—Normal priority
001—Priority level 1
010—Priority level 2
011—Priority level 3
100—Priority level 4
101—Priority level 5
110—Priority level 6
111—Priority level 7 (the highest priority).
type-of-service
value
Type of Service of the data stream. If a packet matches the filter, the
system sets the four bits following the three most significant bits of
the TOS byte to the specified value. The four bits are used to
choose a link according to the type of service. One of the following
values can be specified:
Normal (0)—Normal service.
Disabled (1)—Disables TOS.
Cost (2)—Minimize monetary cost.
Reliability (4)—Maximize reliability.
Throughput (8)—Maximize throughput.
Latency (16)—Minimize delay.
Keyword or argument Description