Net Optics iBypass HD User Manual

Page 34

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iBypass HD

• Heartbeat Mode (mode) – selects whether Heartbeat Packets should be issued from monitor port 1, 2, or both

• Heartbeat Retry Count (retries) – number of times in a row that the Heartbeat packets are missed in order to

trigger Bypass On state; for example, when retries=1, Bypass On is triggered when a single Heartbeat packet is

lost; the value must be in the range of 1 to 10; the default value is 1

• Heartbeat Interval (interval) – number of milliseconds between emitting Heartbeat packets; the value must be

in the range of 1 to 65535; values greater than or equal to 1000 (1 second) are recommended for 1 Gbps bypass

switches; the default value is 1000

• Heartbeat Timeout (timeout) – number of milliseconds to wait for a Heartbeat packet to be returned, before

it is determined to be lost; the value must be in the range of 1 to 65535 and must be less than or equal to the

Heartbeat Interval; the default value is 1000

Use Bypass Switch Pairs in High Availability (HA) Mode

The pair of bypass switches in each DBM can be configured to operate in a HA mode that supports both redundant links

and redundant tools. If you want to operate with both redundant links and redundant tools, choose ha_mode=both.

If you want to operate with redundant links and a single tool, choose ha_mode=link and only the tool set as

primary_tool=<1|2> will be used. To operate with redundant tools and a single link, choose ha_mode=tool and only

the link set as primary_link=<1|2> will be used. Set ha_mode=disable to use the two segments independently, not in

an HA mode.

The following sections describe HA operation when the primary link and primary IPS are active, when the primary link

fails, when the primary IPS fails, and when both the primary link and the primary IPS fails.

HA mode—Normal operation

HA mode enables two links and two IPSs to be connected to a DBM, with the second link and IPS acting as backups for the

primary link and IPS. Normal operation, when both links and both tools are functional, is shown in the following figure:

Passive link

Active link

Internet

X

IPS

Active link

Active link

Passive link

Internet

IPS

Backup IPS

Backup IPS

Normal Operation

Operation When Primary Link Fails

Backup IPS

IPS

X

Operation When Primary IPS Fails

Passive link

Internet

Passive link

Active link

Internet

X

Operation When Primary Link

and Primary IPS Fail

Backup IPS

IPS

X

Figure 18: DBM 1 operating in HA mode

At the top of Figure 18, traffic is shown flowing on the upper link (segment 1) from the Internet, through bypass switch 1

(the primary bypass switch) and IPS, to the router. (It also flows in the opposite direction.) The lower link (segment 2) is a

backup in case the active link fails; the lower link's path through the bypass switch is in Bypass On mode, so traffic can

flow on the link if there is any traffic moving through the backup path.

A second IPS is installed on the monitor ports of bypass switch 2, to act as a backup in case the primary IPS fails.

Heartbeat packets are sent through the backup IPS because bypass switch 2 is in Bypass On mode.

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