PM3350-SW datasheet(80/224 Pages) PMC

80 / 224 page

ELAN 8X10

PM3350 ELAN 8 X10

DATA SHEET

PMC-970109

ISSUE 3

8 PORT ETHERNET SWITCH

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND PMC-SIERRA, INC. CUSTOMERS ONLY

RXFrames128-255:

32-bit count of frames received on this port that ranged between 128 and 255

bytes in size, inclusive.

RXFrames256-511:

32-bit count of frames received on this port that ranged between 256 and 511

bytes in size, inclusive.

RXFrames512-1023:

32-bit count of frames received on this port that ranged between 512 and

1023 bytes in size, inclusive.

RXFrames1024-1518:

32-bit count of frames received on this port that ranged between 1024 and

1518 bytes in size, inclusive.

The FirstDD and the LastDD fields serve to control the transmit queue for the MAC

channel associated with this local port descriptor: the FirstDD contains the 24-bit

memory address of the data descriptor at the head of the queue, while the LastDD field

points to the data descriptor at the tail of the queue. If the queue is empty, the FirstDD

and LastDD fields are set to NULL; otherwise, the fields define a linked-list of data

descriptors that in turn point to the chains of packet buffers containing the Ethernet

frame data that must be transmitted out this physical port. Initially, the FIrstDD and

LastDD fields are set to NULL (i.e., representing an empty transmit queue.) As frames

are queued for transmit, these are changed to point to the respective data descriptors;

as frames are transmitted, they are updated, until finally they return to holding NULL

pointers when no more frames are present on the transmit queue. It is illegal for

anything other than valid Ethernet frames to be queued on the transmit queues

maintained by the local port descriptors.

The NumCollide field is used to track the number of consecutive collisions encountered

when attempting to transmit a given frame. It is cleared to zero prior to starting the

transmit of every frame. If a collision terminates the frame transmission attempt, this

field is incremented by one; if the count of collisions for this frame exceeds the pre-

defined maximum (generally, a default value of 16, according to the IEEE 802.3

standard), then the frame is discarded and an error is reported. The value of the

NumCollide field is also used in generating the backoff counter value according to the

IEEE 802.3 collision backoff algorithm.

The PortNum field contains the logical port number assigned to the physical MAC port

corresponding to this local port descriptor. This field must be set to the physical index of

the MAC port at startup time. The SrcPort field in data descriptors pointing to frames

received on this MAC port is initialized from the PortNum field.

PM3350-SW Datasheet(PDF) 80 Page - PMC-Sierra, Inc

PM3350-SW Datasheet(HTML) 80 Page - PMC-Sierra, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL