[c-nsp] 3560 leaking broadcasts

[Mateusz Blaszczyk]

Hey,

I saw it specifically on 53SE on 3750 (12port)
53SE for 3560 was ok.
It didn't concern me much because it was testlab only and I wasn't
going to use it for production.
BTW 52SE doesn't have this problem.

I think you should open a tac case,

Best Regards,

-mat

On 10 March 2010 07:48, Ian Henderson <ianh at ianh.net.au> wrote:
>
> Hi folks,
>
> Has anyone ever seen broadcasts leaking from an SVI into a layer 3 interface
> on a 3560?
>
> We've got a managed Ethernet link between a 3560G-48TS (Auckland,
> 12.2(50)SE1 IP Services) and a 3750G-24TS (Sydney, 12.2(53)SE IP Services)
> configured as a /31 layer 3 interface on both sides. The link runs OSPF in
> area 64, and PIM sparse mode. Both Sydney and Auckland have a number of
> SVIs.
>
> [Hosts] -- VLAN 11 -- SVI11[Sydney]L3 -- /31 link -- L3[Auckland]
>
> Sydney config:
> interface GigabitEthernet1/0/25
>  description Auckland:Gi0/47
>  no switchport
>  ip address x.x.x.193 255.255.255.254
>  no ip redirects
>  no ip proxy-arp
>  ip pim sparse-mode
>  ip ospf cost 50
>  speed nonegotiate
>  priority-queue out
>  service-policy input SET-DSCP-TRUST
>
> Auckland config:
> interface GigabitEthernet0/47
>  description Sydney:Gi1/0/25
>  no switchport
>  ip address x.x.x.192 255.255.255.254
>  no ip redirects
>  no ip proxy-arp
>  ip pim sparse-mode
>  ip ospf cost 200
>  speed 100
>  duplex full
>  priority-queue out
>  service-policy input SET-DSCP-TRUST
>
> On the Auckland 3560, OSPF constantly reports a mismatched area ID, even
> though the area 64 session is up. PIM shows two neighbors, even though its a
> point to point link. The IP address listed in both messages is the Sydney
> 3750's Vlan11 address.
>
> Mar 10 19:53:14.662 NZDT: %OSPF-4-ERRRCV: Received invalid packet:
> mismatch area ID, from backbone area must be virtual-link but not found
> from x.x.x.138, GigabitEthernet0/47
>
> Auckland#show ip pim nei
> PIM Neighbor Table
> Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
>      P - Proxy Capable, S - State Refresh Capable
> Neighbor          Interface                Uptime/Expires    Ver   DR
> Address
> Prio/Mode
> x.x.x.138     GigabitEthernet0/47      02:25:20/00:01:20 v2    1 / S P
> x.x.x.193     GigabitEthernet0/47      02:25:21/00:01:37 v2    1 / DR S P
>
> Some debugging revealed something odd - when performing 'show mac- address
> xxxx' on the internally assigned VLAN for Gi1/0/25 on Sydney, I see MAC
> addresses listed against VLAN 11.
>
> Sydney#show vlan int usage
>
> VLAN Usage
> ---- --------------------
> 1006 GigabitEthernet1/0/3
> 1007 GigabitEthernet1/0/25
>
> Sydney#show mac- vlan 1007
>          Mac Address Table
> -------------------------------------------
>
> Vlan    Mac Address       Type        Ports
> ----    -----------       --------    -----
>  All    0100.0ccc.cccc    STATIC      CPU
>  All    0100.0ccc.cccd    STATIC      CPU
>  All    0180.c200.0000    STATIC      CPU
>  All    0180.c200.0001    STATIC      CPU
>  All    0180.c200.0002    STATIC      CPU
>  All    0180.c200.0003    STATIC      CPU
>  All    0180.c200.0004    STATIC      CPU
>  All    0180.c200.0005    STATIC      CPU
>  All    0180.c200.0006    STATIC      CPU
>  All    0180.c200.0007    STATIC      CPU
>  All    0180.c200.0008    STATIC      CPU
>  All    0180.c200.0009    STATIC      CPU
>  All    0180.c200.000a    STATIC      CPU
>  All    0180.c200.000b    STATIC      CPU
>  All    0180.c200.000c    STATIC      CPU
>  All    0180.c200.000d    STATIC      CPU
>  All    0180.c200.000e    STATIC      CPU
>  All    0180.c200.000f    STATIC      CPU
>  All    0180.c200.0010    STATIC      CPU
>  All    ffff.ffff.ffff    STATIC      CPU
>  11    0012.80bf.1718    DYNAMIC     Gi1/0/24
>  11    0012.80bf.1743    DYNAMIC     Gi1/0/24
>  11    0015.c695.b495    DYNAMIC     Gi1/0/1
>  11    0015.c6fa.1e35    DYNAMIC     Gi1/0/24
> Total Mac Addresses for this criterion: 24
>
> Sydney#show run int vlan11
> Building configuration...
>
> Current configuration : 185 bytes
> !
> interface Vlan11
>  description ASA Network
>  ip address x.x.x.138 255.255.255.248
>  no ip redirects
>  no ip unreachables
>  no ip proxy-arp
>  ip pim sparse-mode
>  ip ospf cost 5
> end
>
> I quickly threw it together in the lab and couldn't ping between a host on
> the VLAN and Auckland, so suspect its broadcast/multicast traffic only.
>
> Hunting around the network, this appears to happen on every 3560, 3560E, and
> 3750 I could find. 6500 Sup720 doesn't seem to be impacted. Other than the
> error message (which is uncommon, most links are in the same OSPF area) and
> the PIM neighbors (new rollout), I can't see anything thats actually causing
> a problem. Although I'm concerned if there's a broadcast storm, we may
> exhaust bandwidth on routed links.
>
> So, has anyone seen this before? Is it a bug or design limitation on the
> 3560/3750 platform? Is there any other way to make layer 3 interfaces work
> other than a hardware upgrade?
>
> Thanks,
>
>
>
> - I.
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