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Number of ARP Entries Was Greater Than That Supported by an LPUG Board with an Intra-board Trunk

Publication Date:  2013-09-26 Views:  68 Downloads:  0
Issue Description

A trunk on an LPUG/LPUA board on an NE40E/NE80E running V300R003C02B697 contained two member interfaces. A new member interface was added to the trunk for capacity expansion.

Pinging a user from the NE40E/NE80E succeeded, but pinging the user from the network-side upstream device connected to NE40E/NE80E failed.
Handling Process

1. Suspected that the problem was caused by an exception in table entry delivering. The routing table and ARP table needed to be checked.

2. Checked the traffic statistics.

Packets that entered the NE40E/NE80E were not forwarded to a downstream device.

3. Checked the microcodes and chip 587 count.

No obvious packet loss occurred.

4. Checked the logs.

The following information indicates that the number of ARP table entries reached the upper threshold.

Jan  9 2013 03:25:53 XXXXXXXXXXXXXXXXXXXX/NE80E %%01FPI_DBG/6/BBOXCFGFAIL(D):-Slot=1; Config fail reason is Config Paramenter  Invaild. Time=2013:1:9 3:22:12 np_ipv4_arp_entry_add num_req=1

Jan  9 2013 03:25:53 XXXXXXXXXXXXXXXXXXXX/NE80E %%01FPI_DBG/6/BBOXCFGFAIL(D):-Slot=1; Config fail reason is Write TCAM Fail. Time=2013:1:9 3:22:12 np_ipv4_arp_entry_add (req_data_p->prefix_index)=9497

5. Checked the ARP table.

The ARP table contained over 7000 entries. On the LPUA/LPUG/LPUF-10 board, the ARP entries were copied for all member interfaces in a trunk. Because the intra-board trunk contained three member interfaces, the total number of ARP entries was greater than the specifications 20000.

[XXXXXXXXXXXXXXXXXXXX /NE80E]display arp slot 1 statistics

Dynamic:7410    Static:194
Root Cause

The number of ARP table entries was greater than that the LPUA/LPUG/LPUF-10 board supported.

You can run the following command to check whether the actual number of ARP entries is within the specifications: 

<XXXXXXXXXXXX /NE80E>display arp slot 1 statistics------>Command 1

  Dynamic:7894    Static:194 


[hidecmd]dis nps-resm slot 1 tcam------>Command 2


PoolID  ShrTbl  SubTbl  BlkNum   Flag  Count    FLHIdx   BlkSize  BufAddr


[35  ]         -2      35      26624       1     15788        4        4        0x1b622190

The Count column indicates the actual number of TCAM entries. The LPUA, LPUG, and LPUF-10 support a maximum of 26000, 20000, and 100000 TCAM entries.

If trunk contained only two members, Dynamic: X x 2 in command 1 is slight smaller than the value under count in command 2.