Browse Prior Art Database

Method to Protect Mission Critical Devices From Losing Network Connectivity

IP.com Disclosure Number: IPCOM000236791D
Publication Date: 2014-May-15
Document File: 5 page(s) / 472K

Publishing Venue

The IP.com Prior Art Database

Abstract

Described is a method to protect mission critical devices from losing network connectivity

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 53% of the total text.

Page 01 of 5

Method to Protect Mission Critical Devices From Losing Network Connectivity

In a PureFlex management network, it is critical that the CMM (Chassis Management Module) maintains network connectivity to all the compute nodes and IOMs (I/O Module switch) on the internal management network. Currently, a loop in the customer's network can cause loss of connectivity to compute nodes connected to the internal management network, since there is no isolation between the internal and external management networks.

    This invention will prevent a loop in the external customer network from disrupting connectivity to nodes on the internal management network. The PureFlex nodes can still be managed while the customer attempts to resolve the loop in the customer network. In addition to network loop protection, the internal management network is protected against MAC spoofing.

    Figure 1 illustrates how a loop in the external network can disrupt network connectivity to a device attached to an internal network. Description of steps in Figure 1:

Device D2.1 sends a broadcast packet (e.g., ARP) with source address M2.1.


1.

Switch SW2 forwards the broadcast packet to switch SW1.


2.

Switch SW1 forwards the broadcast packet to switch SW3.


3.

Switch SW3 forwards the broadcast packet back to switch SW2 creating an network loop.


4.

Switch SW2 moves MAC M2.1 from an access (downlink) port connected to internal


5.

network 2 to an uplink port. Network connectivity to device D2.1 is lost.

    Note, if switch SW2 has a loop detection feature enabled, it should eventually detect the network loop and stop forwarding the broadcast packet. However, its MAC table has already been compromised and connectivity to device M2.1 has been lost.

Figure 1 - Network Loop

    
Figure 2 illustrates how an attacker can use MAC spoofing to cause a denial of service and/or potential access customer data. Description of steps in Figure 2:

1


Page 02 of 5


1.

The attacker steals MAC M2.1 owned by device D2.1 and crafts a malicious packet destined for device D2.2.

Attack device D3.2 sends the malicious packet to switch SW3.

Switch SW3 forwards the malicious packet to switch SW2.

Switch SW2 moves MAC M2.1 from an access (downlink) port connected to internal network 2 to an uplink port. All packets destined to device D2.1 will now be forwarded to the attack device D3.2.

Switch SW2 forwards the malicious packet to device D2.2.

Device D2.2 thinks it is talking to the real device D2.1 and sends a reply packet.

Unbeknownst to device D2.2, the reply packet will be forwarde...