LevelOne GTL-2691 User Manual

Page 983

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C

HAPTER

30

| Access Control Lists

IPv6 ACLs

– 983 –

flow-label – A label for packets belonging to a particular traffic

“flow” for which the sender requests special handling by IPv6

routers, such as non-default quality of service or “real-time” service

(see RFC 2460). (Range: 0-16777215)
next-header – Identifies the type of header immediately following

the IPv6 header. (Range: 0-255)
time-range-name - Name of the time range.

(Range: 1-30 characters)

D

EFAULT

S

ETTING

None

C

OMMAND

M

ODE

Extended IPv6 ACL

C

OMMAND

U

SAGE

All new rules are appended to the end of the list.

A flow label is assigned to a flow by the flow's source node. New flow

labels must be chosen pseudo-randomly and uniformly from the range

1 to FFFFF hexadecimal. The purpose of the random allocation is to

make any set of bits within the Flow Label field suitable for use as a

hash key by routers, for looking up the state associated with the flow.
A flow identifies a sequence of packets sent from a particular source to

a particular (unicast or multicast) destination for which the source

desires special handling by the intervening routers. The nature of that

special handling might be conveyed to the routers by a control protocol,

such as a resource reservation protocol, or by information within the

flow's packets themselves, e.g., in a hop-by-hop option. A flow is

uniquely identified by the combination of a source address and a non-

zero flow label. Packets that do not belong to a flow carry a flow label of

zero.
Hosts or routers that do not support the functions specified by the flow

label must set the field to zero when originating a packet, pass the field

on unchanged when forwarding a packet, and ignore the field when

receiving a packet.

Optional internet-layer information is encoded in separate headers that

may be placed between the IPv6 header and the upper-layer header in

a packet. There are a small number of such extension headers, each

identified by a distinct Next Header value. IPv6 supports the values

defined for the IPv4 Protocol field in RFC 1700, including these

commonly used headers:
0 : Hop-by-Hop Options

(RFC 2460)

6 : TCP Upper-layer Header

(RFC 1700)

17 : UDP Upper-layer Header

(RFC 1700)

43 : Routing

(RFC 2460)

44 : Fragment

(RFC 2460)

51 : Authentication

(RFC 2402)

50 : Encapsulating Security Payload (RFC 2406)

60 : Destination Options

(RFC 2460)

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