PM3350-SW datasheet(76/224 Pages) PMC

76 / 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

DstHBIndx:

16-bit encoded index of destination hash bucket found by address table

lookup hardware.

The NextDD, FirstPB, NumPBs, LastPB and SrcPort fields all correspond to the

similarly named fields in normal data descriptors, and perform the same functions. The

Flags field, however, is formatted in a slightly different manner, as shown below:

76543210

0001

ARPT

Dribble

DMiss

SMiss

SMiss:

If set, indicates that the SrcHBIndx field is invalid (the address table lookup

hardware did not find a match for the source MAC address).

DMiss:

If set, indicates that the DstHBIndx field is invalid (the address table lookup

hardware did not find a match for the destination MAC address).

Dribble:

Indicates a dribble bit error during the reception of the frame (i.e., additional

bits were received beyond the end of the frame, but the CRC was found to be

valid).

ARPT:

If set, denotes that the 16-bit EtherType field within the frame contains the

type code assigned to Address Resolution Protocol (ARP) frames (0x0806

hexadecimal).

The SMiss and DMiss bits signify, if set, that the address lookup failed for the source

and destination MAC addresses, respectively. This notification is supplied by the

address table lookup hardware after it attempts to search the hash table for the 48-bit

MAC addresses in the received frame. The Dribble bit is used to signal the switching

firmware that a dribble error was detected during the reception of the frame, and the

suitable dribble error counter should be updated. Finally, the ARPT bit is set whenever

the EtherType field of the received frame (corresponding to the IEEE 802.3 Length

field) equals the value assigned to ARP frames, or 0x0806 hex.

The SrcHBIndx and DstHBIndx fields contain the encoded 16-bit indices of the 24-bit

source and destination hash buckets, respectively, that are returned by the address

table lookup hardware after a search for the MAC addresses within the Ethernet frame.

(If either of the searches fail, then the corresponding field contains invalid information,

and should not be used.) The encoding is performed by first subtracting the 24-bit base

address of the start of the hash bucket array to produce an offset into the array (rather

than the absolute address returned by the address table lookup hardware), and then

PM3350-SW Datasheet(PDF) 76 Page - PMC-Sierra, Inc

PM3350-SW Datasheet(HTML) 76 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