PBB

class os_ken.lib.packet.pbb.itag(pcp=0, dei=0, uca=0, sid=0)

I-TAG (IEEE 802.1ah-2008) header encoder/decoder class.

An instance has the following attributes at least. Most of them are same to the on-wire counterparts but in host byte order. __init__ takes the corresponding args in this order.

Attribute	Description
pcp	Priority Code Point
dei	Drop Eligible Indication
uca	Use Customer Address
sid	Service Instance ID

classmethod parser(buf)

Decode a protocol header.

This method is used only when decoding a packet.

Decode a protocol header at offset 0 in bytearray buf. Returns the following three objects.

• An object to describe the decoded header.

• A packet_base.PacketBase subclass appropriate for the rest of the packet. None when the rest of the packet should be considered as raw payload.

• The rest of packet.

serialize(payload, prev)

Encode a protocol header.

This method is used only when encoding a packet.

Encode a protocol header. Returns a bytearray which contains the header.

payload is the rest of the packet which will immediately follow this header.

prev is a packet_base.PacketBase subclass for the outer protocol header. prev is None if the current header is the outer-most. For example, prev is ipv4 or ipv6 for tcp.serialize.