Diameter Signaling Router (DSR) Why the Buffer Ring Size for NIC Card on IPFE Blades is 4078 ?

Asset ID:	1-71-2157518.1
Update Date:	2016-07-19
Keywords:

Solution Type Technical Instruction Sure

Solution 2157518.1 : Diameter Signaling Router (DSR) Why the Buffer Ring Size for NIC Card on IPFE Blades is 4078 ?

Applies to:

Oracle Communications Diameter Signaling Router (DSR) - Version DSR 5.0 and later
Information in this document applies to any platform.

Goal

On What Basis Buffer Ring Size is set as 4078 in ETHTOOL_OPTS when we do IPFE Configuration under DSR Software Installation and Configuration Procedure (E58954):

Procedure 30 : IPFE Configuration

Step 6 Check the Interface Configuration

$ sudo cat /etc/sysconfig/network-scripts/ifcfg-eth01
ETHTOOL_OPTS="--set-ring eth01 rx 4078; --offload eth0X gro off gso off"

Solution

The RX Ring Size is the kernel of Linux buffer ring size (0-4078).

HP Enclosure blades will have NIC card from Broadcom NetXtream II. IPFE uses the maximum of buffer ring size supported by Broadcom NetXtream II NIC Card i.e. 4078.

From the document https://www.broadcom.com/docs/support/ethernet_nic/Broadcom_NetXtremeII_Server_T7.8.pdf which has below details for the Driver of NIC Card :

DRIVER DEFAULTS
Speed: Autonegotiation with all speeds advertised
Flow Control: Autonegotiation with rx and tx advertised
MTU: 1500 (range 46–9000)
Rx Ring Size : 4078 (range 0–4078)
Tx Ring Size : 4078 (range (MAX_SKB_FRAGS+4) - 4078). MAX_SKB_FRAGS varies on different kernels and different architectures. On a 2.6 kernel for x86, MAX_SKB_FRAGS is 18.
Coalesce RX Microseconds: 25 (range 0–3000)
Coalesce TX Microseconds: 50 (range 0–12288)
MSI-X: Enabled (if supported by 2.6 kernel)
TSO: Enabled
WoL: Disabled

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