[c-nsp] Cisco 2970 Switch v Microsoft NLB

[Brian Desmond]

This is expected behavior as to how NLB works...If you don't want this
you need to add a static arp entry as you did.

The other option is to build a dedicated VLAN for the cluster's load
balanced subnet/interfaces. 

This is a useful blog entry on this -
http://msmvps.com/blogs/clusterhelp/archive/2006/06/24/102772.aspx


Thanks,
Brian Desmond
brian at briandesmond.com

c - 312.731.3132


> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of Devon True
> Sent: Thursday, July 13, 2006 6:25 PM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Cisco 2970 Switch v Microsoft NLB
> 
> All:
> 
> I have an issue where a Cisco 2970 switch will not add a dynamic MAC
> address for a NLB IP address in its mac-address-table. The NLB MAC
> address is 02bf.0a00.0273.
> 
> Any packets destined for the NLB MAC address gets broadcasted out all
> ports (I used Ethereal to capture the traffic) causing unnecessary
> network traffic. I resolved the problem by adding a static
mac-address-
> table entry on the 2970 switch.
> 
> 	mac-address-table static 02bf.0a00.0273 vlan 1 interface
> GigabitEthernet0/3
> 
> I also read the previous cisco-nsp thread about this issue but it
> concerned Cisco routers and not switches. I assume this may be general
> IOS behavior? The upstream device from the switch is a Cisco PIX that
> has static(inside,outside) commands to MAP the external/internal IP
> addresses. The PIX does not seem to have the same issue since there
are
> not static ARP entries configured.
> 
> Previous cisco-nsp thread:
> <http://thread.gmane.org/gmane.network.nsp.cisco/25944/focus=26034>
> 
> Has anyone seen this issue before? I can remove the static
mac-address-
> table entry and the site still works, but there is a mini-broadcast
> storm out every port.
> 
> --- show version ---
> 
> Cisco Internetwork Operating System Software IOS (tm) C2970 Software
> (C2970-I6L2-M), Version 12.1(19)EA1d, RELEASE SOFTWARE (fc1) Copyright
> (c) 1986-2004 by cisco Systems, Inc.
> Compiled Mon 05-Apr-04 20:42 by antonino Image text-base: 0x00003000,
> data-base: 0x006A5954
> 
> ROM: Bootstrap program is C2970 boot loader
> BOOTLDR: C2970 Boot Loader (C2970-HBOOT-M) Version 12.1(14r)EA1a,
> RELEASE SOFTWA RE (fc1)
> 
> tp-prod-sw1 uptime is 1 hour, 59 minutes System returned to ROM by
> power-on System image file is "flash:c2970-i6l2-mz.121-19.EA1d/c2970-
> i6l2-mz.121-19.EA1d.bin"
> 
> cisco WS-C2970G-24TS-E (PowerPC405) processor (revision E0) with
> 118776K/12288K bytes of memory.
> Processor board ID CSG0836P0SP
> Last reset from power-on
> 1 Virtual Ethernet/IEEE 802.3  interface(s)
> 28 Gigabit Ethernet/IEEE 802.3 interface(s) The password-recovery
> mechanism is enabled.
> 
> 512K bytes of flash-simulated non-volatile configuration memory.
> Base ethernet MAC Address       : 00:12:01:0A:81:80
> Motherboard assembly number     : 73-9095-04
> Power supply part number        : 341-0045-01
> Motherboard serial number       : CAT083602U8
> Power supply serial number      : LIT083207DB
> Model revision number           : E0
> Motherboard revision number     : A0
> Model number                    : WS-C2970G-24TS-E
> System serial number            : CSG0836P0SP
> Top Assembly Part Number        : 800-24261-01
> Top Assembly Revision Number    : F0
> Hardware Board Revision Number  : 0x02
> 
> 
> Switch   Ports  Model              SW Version              SW Image
> ------   -----  -----              ----------              ----------
> *    1   28     WS-C2970G-24TS-E   12.1(19)EA1d
C2970-I6L2-M
> 
> 
> Configuration register is 0xF
> 
> ------------------------------
> 
> Thanks,
> 
> Devon
> 
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