MT92220 Datasheet, PDF (59/210 Pages) Zarlink Semiconductor Inc – 1023 Channel Voice Over IP/AAL2 Processor

Data Sheet
MT92220
Field
Description
Next Profile
LHR
FTE
RUN
RTD
LHR HP
LHR LP
When this structure matches and the RUN (Route Using Next profile) bit is ‘1’, this is the
profile number that will be used to search for the packet in the binary tree.
Link Header Replace. When ‘1’, the ATM header and UU/CPI may be changed before
the packet is routed to its destination(s).
When ‘1’, the flow table will be consulted to know if the hit is valid.
Route Using Next profile. When ‘1’ and the packet matches this post-search
confirmation structure, it will be searched for in the binary tree using Next Profile as a
profile number.
Routing Destination.
“000000000” = Delete;
“1xxxxxxxx” = reserved;
“x1xxxxxxx” = TX Link A HP;
“xx1xxxxxx” = TX Link A LP;
“xxx1xxxxx” = TX Link B LP;
“xxxx1xxxx” = TX Link B HP;
“xxxxx1xxx” = reserved;
“xxxxxx1xx” = Network CPU Packet Buffer;
“xxxxxxx1x” = Disassembly;
“xxxxxxxx1” = Packet Identifier;
others = reserved.
Indicates whether this packet’s ATM header and UU/CPI should be changed when the
packet is routed in high priority. “1x” = change ATM header, “x1” = change UU/CPI.
When one of these bits is ‘1’, LHR must also be ‘1’.
Indicates whether this packet’s ATM header and UU/CPI should be changed when the
packet is routed in low priority. “1x” = change ATM header, “x1” = change UU/CPI. When
one of these bits is ‘1’, LHR must also be ‘1’.
Table 19 - Fields and Description
The matching confirmation structure is then consulted to determine the fate of the packet: in this case, the structure
indicates that a new search should be performed, using another profile!
The new profile entry is consulted and it requires a search using the Destination IP address, the Source IP address,
the Destination UDP port, and the source UDP port. The new key is then generated using the CRC and profile
number and searched for in the binary tree. The hit is then compared to the matching post-search confirmation
structure which, in this case, indicates that a new search should be performed again with another profile number.
Then the chip will repeat the above search procedure with using the Destination IP address and the Destination
UDP port, and come back to the matching post-search confirmation structure. This time, the required destination is
the packet disassembly module. Thus the packet is sent to the disassembly module and the next packet can be
treated.
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