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Example: Determining Member Health Using an MX Series Virtual Chassis Heartbeat Connection with Member Routers in Different Subnets
A heartbeat connection is an IP-based, bidirectional packet connection in an MX Series Virtual Chassis between the Virtual Chassis primary and backup routers. The heartbeat packets exchanged over this connection provide critical information about the availability and health of each member router. Starting in Junos OS Release 14.1, you can configure a heartbeat connection in an MX Series Virtual Chassis.
This example describes how to configure a heartbeat connection in an MX Series Virtual Chassis when the member routers reside in different subnets. For information about configuring a heartbeat connection when the Virtual Chassis member routers reside in the same subnet, see Example: Determining Member Health Using an MX Series Virtual Chassis Heartbeat Connection with Member Routers in the Same Subnet.
Requirements
This example uses the following software and hardware components:
Junos OS Release 14.1 and later releases
One MX240 Universal Routing Platform
One MX480 Universal Routing Platform
This configuration example has been tested using the software release listed and is assumed to work on all later releases.
We recommend that you use the commit synchronize command to save any configuration changes to the Virtual Chassis.
For an MX Series Virtual Chassis, the force option is the
default and only behavior when you issue the commit synchronize command. Issuing the commit synchronize command for an
MX Series Virtual Chassis configuration has the same effect as issuing
the commit synchronize force command.
Before you configure a heartbeat connection for a Virtual Chassis:
Configure a Virtual Chassis consisting of two MX Series routers.
As part of the preprovisioned Virtual Chassis configuration shown in the configuration example, you must create and apply the
member0-re0,member0-re1,member1-re0, andmember1-re1configuration groups for each member Routing Engine. Each configuration group includes a unique IP address for the management Ethernet interface (fxp0) on each Routing Engine.Note:When you create the preprovisioned Virtual Chassis configuration at the
[edit virtual-chassis]hierarchy level, make sure you do not configure theno-split-detectionstatement to disable detection of a split in the Virtual Chassis. Using theno-split-detectionstatement is prohibited when you configure a Virtual Chassis heartbeat connection, and doing so causes the commit operation to fail.Ensure TCP connectivity between the primary Routing Engine in the Virtual Chassis primary router (VC-Pp) and the primary Routing Engine in the Virtual Chassis backup router (VC-Bp).
The Virtual Chassis heartbeat connection opens a proprietary TCP port numbered 33087 on the VC-Pp to listen for heartbeat messages. If your network design includes firewalls or filters, make sure the network allows traffic between TCP port 33087 on the VC-Pp and the dynamically allocated TCP port on the VC-Bp.
Overview
A heartbeat connection is an IP-based, bidirectional packet connection between the primary router and backup router in an MX Series Virtual Chassis. The member routers forming the heartbeat connection exchange heartbeat packets that provide critical information about the availability and health of each member router. During a disruption or split in the Virtual Chassis configuration, the heartbeat connection prevents the member routers from changing primary role roles unnecessarily, which can cause undesirable results.
This example configures a heartbeat connection for an MX Series
Virtual Chassis in which the two member routers, each with dual Routing
Engines installed, reside in different subnets. Member router gladius resides in subnet 10.4.0.0/16 and is the global primary
router for the Virtual Chassis (VC-P). Member router trefoil resides in subnet 10.5.0.0/16 and is the global backup router (VC-B)
for the Virtual Chassis. The heartbeat connection is configured between
the primary Routing Engine in gladius (represented by VC-Pp
or member0-re0) and the primary Routing Engine in trefoil (represented by VC-Bp or member1-re0).
Configuring a heartbeat connection for an MX Series Virtual Chassis when the member routers reside in different subnets consists of the following tasks:
Configure two
master-onlyIP addresses for thefxp0management interface: one for the member routers in subnet 10.4.0.0, and a different address for the member routers in subnet 10.5.0.0.Configure a network path for the heartbeat connection to ensure that both member routers can reach each other’s networks.
This example creates static routes to both subnet 10.4.0.0 and subnet 10.5.0.0 on each member router.
Configure the Virtual Chassis heartbeat address for each member Routing Engine to cross-connect to the
master-onlyIP address for the corresponding member Routing Engine in the other subnet.(Optional) Configure a nondefault value for the Virtual Chassis heartbeat timeout interval.
To establish the heartbeat connection in a two-member MX Series
Virtual Chassis, you must configure the heartbeat address to establish
the connection between the primary and backup member routers. To ensure
consistent access to the primary Routing Engine in the Virtual Chassis
primary router (VC-Pp) regardless of which Routing Engine is currently
active, you set the heartbeat address to the previously configured master-only IP address for the fxp0 management
interface.
Because the Virtual Chassis member routers in this example are
in different subnets, you must configure a heartbeat address for each
Routing Engine to enable a cross-connection to the master-only IP address for the corresponding Routing Engine in the other subnet,
as shown in Table 1:
Routing Engine |
Subnet |
Cross-connected Routing Engine |
Heartbeat Address |
|---|---|---|---|
|
10.4.0.0/16 |
|
10.5.2.210 |
|
10.4.0.0/16 |
|
10.5.2.210 |
|
10.5.0.0/16 |
|
10.4.2.210 |
|
10.5.0.0/16 |
|
10.4.2.210 |
Topology
This example configures a heartbeat connection for an MX Series Virtual Chassis with member routers residing in different subnets. For redundancy, each member router is configured with two Virtual Chassis ports.
Table 2 shows the hardware and software configuration settings for each MX Series router in the Virtual Chassis.
Router Name |
Hardware |
Serial Number |
Member ID |
Role |
Virtual Chassis Ports |
Subnet |
|---|---|---|---|---|---|---|
gladius |
MX240 router with:
|
JN10C7135AFC |
0 |
routing-engine (primary) |
vcp-2/2/0vcp-2/3/0 |
10.4.0.0/16 |
trefoil |
MX480 router with:
|
JN115D117AFB |
1 |
routing-engine (backup) |
vcp-2/0/0vcp-5/2/0 |
10.5.0.0/16 |
Configuration
To configure a heartbeat connection in an MX Series Virtual Chassis with member routers in different subnets, perform these tasks:
- CLI Quick Configuration
- Configuring a Consistent Management IP Address for Each Routing Engine
- Configuring Static Routes for Both Subnets on Each Routing Engine
- Configuring the Heartbeat Address and Heartbeat Timeout
CLI Quick Configuration
To quickly configure a heartbeat connection for a Virtual Chassis with with member routers in different subnets, copy the following commands and paste them into the router terminal window:
[edit] set groups member0-re0 interfaces fxp0 unit 0 family inet address 10.4.2.210/16 master-only set groups member0-re1 interfaces fxp0 unit 0 family inet address 10.4.2.210/16 master-only set groups member1-re0 interfaces fxp0 unit 0 family inet address 10.5.2.210/16 master-only set groups member1-re1 interfaces fxp0 unit 0 family inet address 10.5.2.210/16 master-only set groups member0-re0 routing-options static route 10.4.0.0/16 next-hop 10.4.0.1 set groups member0-re0 routing-options static route 10.4.0.0/16 retain set groups member0-re0 routing-options static route 10.4.0.0/16 no-readvertise set groups member0-re0 routing-options static route 10.5.0.0/16 next-hop 10.4.0.1 set groups member0-re0 routing-options static route 10.5.0.0/16 retain set groups member0-re0 routing-options static route 10.5.0.0/16 no-readvertise set groups member0-re1 routing-options static route 10.4.0.0/16 next-hop 10.4.0.1 set groups member0-re1 routing-options static route 10.4.0.0/16 retain set groups member0-re1 routing-options static route 10.4.0.0/16 no-readvertise set groups member0-re1 routing-options static route 10.5.0.0/16 next-hop 10.4.0.1 set groups member0-re1 routing-options static route 10.5.0.0/16 retain set groups member0-re1 routing-options static route 10.5.0.0/16 no-readvertise set groups member1-re0 routing-options static route 10.5.0.0/16 next-hop 10.5.0.1 set groups member1-re0 routing-options static route 10.5.0.0/16 retain set groups member1-re0 routing-options static route 10.5.0.0/16 no-readvertise set groups member1-re0 routing-options static route 10.4.0.0/16 next-hop 10.5.0.1 set groups member1-re0 routing-options static route 10.4.0.0/16 retain set groups member1-re0 routing-options static route 10.4.0.0/16 no-readvertise set groups member1-re1 routing-options static route 10.5.0.0/16 next-hop 10.5.0.1 set groups member1-re1 routing-options static route 10.5.0.0/16 retain set groups member1-re1 routing-options static route 10.5.0.0/16 no-readvertise set groups member1-re1 routing-options static route 10.4.0.0/16 next-hop 10.5.0.1 set groups member1-re1 routing-options static route 10.4.0.0/16 retain set groups member1-re1 routing-options static route 10.4.0.0/16 no-readvertise set groups member0-re0 virtual-chassis heartbeat-address 10.5.2.210 set groups member0-re1 virtual-chassis heartbeat-address 10.5.2.210 set groups member1-re0 virtual-chassis heartbeat-address 10.4.2.210 set groups member1-re1 virtual-chassis heartbeat-address 10.4.2.210 set virtual-chassis heartbeat-timeout 10
Configuring a Consistent Management IP Address for Each Routing Engine
Step-by-Step Procedure
In addition to configuring a unique IP address for the fxp0 management interface on each Routing Engine when you first
set up the Virtual Chassis, you must configure additional management
IP addresses, known as the master-only address, to ensure
consistent access to the fxp0 management interface on the
primary Routing Engine in the Virtual Chassis primary router (VC-Pp).
The master-only address is active only on the management
interface for the VC-Pp. During a switchover, the master-only address moves to the new Routing Engine currently functioning as
the VC-Pp.
Because the Virtual Chassis primary router and backup router
in this example reside in different subnets, you must configure two
different master-only IP addresses: one for the Routing
Engines in subnet 10.4.0.0/16 (member0-re0 and member0-re1), and one for the Routing Engines in subnet 10.5.0.0/16 (member1-re0 and member1-re1). You then configure these master-only addresses as the subnet-specific heartbeat addresses to establish
the heartbeat connection. For more information about the cross-connections
in this example, see Table 1.
To configure the primary-only fxp0 IP address for
each Routing Engine:
From the console on member 0, configure the IP address for the
fxp0management interface for the Routing Engines in subnet 10.4.0.0/16.{master:member0-re0}[edit] user@gladius# set groups member0-re0 interfaces fxp0 unit 0 family inet address 10.4.2.210/16 primary-only user@gladius# set groups member0-re1 interfaces fxp0 unit 0 family inet address 10.4.2.210/16 master-onlyFrom the console on member 0, configure the IP address for the
fxp0management interface for the Routing Engines in subnet 10.5.0.0/16.{master:member0-re0}[edit] user@gladius# set groups member1-re0 interfaces fxp0 unit 0 family inet address 10.5.2.210/16 primary-only user@gladius# set groups member1-re1 interfaces fxp0 unit 0 family inet address 10.5.2.210/16 master-only
Results
From the console on the Virtual Chassis primary router, display the results of the configuration. For brevity, portions of the configuration unrelated to this procedure are replaced by an ellipsis (...).
For member0-re0:
{master:member0-re0}[edit]
user@gladius# show groups member0-re0
system {
host-name gladius;
backup-router 10.4.0.1 destination [ 172.16.0.0/12 ... 10.204.0.0/16 ];
}
interfaces {
fxp0 {
unit 0 {
family inet {
address 10.4.2.100/16;
address 10.4.2.210/16 {
master-only;
}
}
}
}
}
For member0-re1:
{master:member0-re0}[edit]
user@gladius# show groups member0-re1
system {
host-name gladius1;
backup-router 10.4.0.1 destination [ 172.16.0.0/12 ... 10.204.0.0/16 ];
}
interfaces {
fxp0 {
unit 0 {
family inet {
address 10.4.2.101/16;
address 10.4.2.210/16 {
master-only;
}
}
}
}
}
For member1-re0:
{master:member0-re0}[edit]
user@gladius# show groups member1-re0
system {
host-name trefoil;
backup-router 10.5.0.1 destination [ 172.16.0.0/12 ... 10.204.0.0/16 ];
}
interfaces {
fxp0 {
unit 0 {
family inet {
address 10.5.3.101/16;
address 10.5.2.210/16 {
master-only;
}
}
}
}
}
For member1-re1:
{master:member0-re0}[edit]
user@gladius# show groups member1-re1
system {
host-name trefoil1;
backup-router 10.5.0.1 destination [ 172.16.0.0/12 ... 10.204.0.0/16 ];
}
interfaces {
fxp0 {
unit 0 {
family inet {
address 10.5.3.102/16;
address 10.5.2.210/16 {
master-only;
}
}
}
}
}
If you are done configuring the device, enter commit from configuration mode.
Configuring Static Routes for Both Subnets on Each Routing Engine
Step-by-Step Procedure
You must configure secure and reliable routes for subnets 10.4.0.0/16 and 10.5.0.0/16 on each Routing Engine for the exchange of TCP/IP heartbeat packets. The heartbeat packets provide critical information about the availability and health of each member router.
The routes you configure for the heartbeat connection must be
independent of the Virtual Chassis port links. Specifically, you must
ensure that the primary Routing Engine in the Virtual Chassis backup
router (VC-Bp) can make a TCP/IP connection to the master-only IP address of the primary Routing Engine in the Virtual Chassis
primary router (VC-Pp).
This examples creates static routes to both subnets on each member Routing Engine to configure the heartbeat path. However, you can choose the method that best meets your needs to configure the heartbeat path for member routers in different subnets.
We recommend that you use the router management
interface (fxp0) as the heartbeat path. The management
interface is generally available earlier than the line card interfaces,
and is typically connected to a more secure network than the other
interfaces.
To create static routes for subnets 10.4.0.0/16 and 10.5.0.0/16 on each Routing Engine:
Log in to the console on member 0 (Virtual Chassis primary router).
Configure the static routes for
member0-re0.{master:member0-re0}[edit] user@gladius# set groups member0-re0 routing-options static route 10.4.0.0/16 next-hop 10.4.0.1 user@gladius# set groups member0-re0 routing-options static route 10.4.0.0/16 retain user@gladius# set groups member0-re0 routing-options static route 10.4.0.0/16 no-readvertise user@gladius# set groups member0-re0 routing-options static route 10.5.0.0/16 next-hop 10.4.0.1 user@gladius# set groups member0-re0 routing-options static route 10.5.0.0/16 retain user@gladius# set groups member0-re0 routing-options static route 10.5.0.0/16 no-readvertiseConfigure the static routes for
member0-re1.{master:member0-re0}[edit] user@gladius# set groups member0-re1 routing-options static route 10.4.0.0/16 next-hop 10.4.0.1 user@gladius# set groups member0-re1 routing-options static route 10.4.0.0/16 retain user@gladius# set groups member0-re1 routing-options static route 10.4.0.0/16 no-readvertise user@gladius# set groups member0-re1 routing-options static route 10.5.0.0/16 next-hop 10.4.0.1 user@gladius# set groups member0-re1 routing-options static route 10.5.0.0/16 retain user@gladius# set groups member0-re1 routing-options static route 10.5.0.0/16 no-readvertiseConfigure the static routes for
member1-re0.{master:member0-re0}[edit] user@gladius# set groups member1-re0 routing-options static route 10.5.0.0/16 next-hop 10.5.0.1 user@gladius# set groups member1-re0 routing-options static route 10.5.0.0/16 retain user@gladius# set groups member1-re0 routing-options static route 10.5.0.0/16 no-readvertise user@gladius# set groups member1-re0 routing-options static route 10.4.0.0/16 next-hop 10.5.0.1 user@gladius# set groups member1-re0 routing-options static route 10.4.0.0/16 retain user@gladius# set groups member1-re0 routing-options static route 10.4.0.0/16 no-readvertiseConfigure the static routes for
member1-re1.{master:member0-re0}[edit] user@gladius# set groups member1-re1 routing-options static route 10.5.0.0/16 next-hop 10.5.0.1 user@gladius# set groups member1-re1 routing-options static route 10.5.0.0/16 retain user@gladius# set groups member1-re1 routing-options static route 10.5.0.0/16 no-readvertise user@gladius# set groups member1-re1 routing-options static route 10.4.0.0/16 next-hop 10.5.0.1 user@gladius# set groups member1-re1 routing-options static route 10.4.0.0/16 retain user@gladius# set groups member1-re1 routing-options static route 10.4.0.0/16 no-readvertise
Results
Display the results of the configuration. For brevity, portions of the configuration unrelated to this procedure are replaced by an ellipsis (...).
For member0-re0:
{master:member0-re0}[edit]
user@gladius# show groups member0-re0 routing-options static
route 10.4.0.0/16 {
next-hop 10.4.0.1;
retain;
no-readvertise;
}
route 10.5.0.0/16 {
next-hop 10.4.0.1;
retain;
no-readvertise;
}
...
For member0-re1:
{master:member0-re0}[edit]
user@gladius# show groups member0-re1 routing-options static
route 10.4.0.0/16 {
next-hop 10.4.0.1;
retain;
no-readvertise;
}
route 10.5.0.0/16 {
next-hop 10.4.0.1;
retain;
no-readvertise;
}
...
For member1-re0:
{master:member0-re0}[edit]
user@gladius# show groups member1-re0 routing-options static
route 10.5.0.0/16 {
next-hop 10.5.0.1;
retain;
no-readvertise;
}
route 10.4.0.0/16 {
next-hop 10.5.0.1;
retain;
no-readvertise;
}
...
For member1-re1:
{master:member0-re0}[edit]
user@gladius# show groups member1-re1 routing-options static
route 10.5.0.0/16 {
next-hop 10.5.0.1;
retain;
no-readvertise;
}
route 10.4.0.0/16 {
next-hop 10.5.0.1;
retain;
no-readvertise;
}
...
If you are done configuring the device, enter commit from configuration mode.
Configuring the Heartbeat Address and Heartbeat Timeout
Step-by-Step Procedure
To enable cross-connection between Virtual Chassis member
routers in different subnets, you configure 10.5.2.210, which is the master-only IP address for the Routing Engines in subnet 10.5.0.0/16,
as the heartbeat address for the Routing Engines in subnet 10.4.0.0/16
(member0-re0 and member0-re1). Conversely, you
configure 10.4.2.210, which is the master-only IP address
for the Routing Engines in subnet 10.4.0.0/16, as the heartbeat address
for the Routing Engines in subnet 10.5.0.0/16 (member1-re0 and member1-re1). For more information about the cross-connections
in this example, see Table 1.
Optionally, you can also configure a nondefault value for the heartbeat timeout interval. The heartbeat timeout is the maximum time within which a Virtual Chassis member router must respond to a heartbeat packet sent by the other member router. If you do not explicitly configure the heartbeat timeout interval, the default value (2 seconds) applies.
To configure the heartbeat address and heartbeat timeout:
Log in to the console on member 0 (Virtual Chassis primary router).
Configure the heartbeat address for each Routing Engine.
{master:member0-re0}[edit] user@gladius# set groups member0-re0 virtual-chassis heartbeat-address 10.5.2.210 user@gladius# set groups member0-re1 virtual-chassis heartbeat-address 10.5.2.210 user@gladius# set groups member1-re0 virtual-chassis heartbeat-address 10.4.2.210 user@gladius# set groups member1-re1 virtual-chassis heartbeat-address 10.4.2.210(Optional) Configure a nondefault value for the heartbeat timeout interval.
{master:member0-re0}[edit] user@gladius# set virtual-chassis heartbeat-timeout 10
Results
Display the results of the configuration.
For member0-re0:
{master:member0-re0}[edit]
user@gladius# show groups member0-re0 virtual-chassis
preprovisioned;
traceoptions {
file VCCP size 100m;
flag all;
}
heartbeat-address 10.5.2.210;
heartbeat-timeout 10;
member 0 {
role routing-engine;
serial-number JN10C7135AFC;
}
member 1 {
role routing-engine;
serial-number JN115D117AFB;
}
For member0-re1:
{master:member0-re0}[edit]
user@gladius# show groups member0-re1 virtual-chassis
preprovisioned;
traceoptions {
file VCCP size 100m;
flag all;
}
heartbeat-address 10.5.2.210;
heartbeat-timeout 10;
member 0 {
role routing-engine;
serial-number JN10C7135AFC;
}
member 1 {
role routing-engine;
serial-number JN115D117AFB;
}
For member1-re0:
{master:member0-re0}[edit]
user@gladius# show groups member1-re0 virtual-chassis
preprovisioned;
traceoptions {
file VCCP size 100m;
flag all;
}
heartbeat-address 10.4.2.210;
heartbeat-timeout 10;
member 0 {
role routing-engine;
serial-number JN10C7135AFC;
}
member 1 {
role routing-engine;
serial-number JN115D117AFB;
}
For member1-re1:
{master:member0-re0}[edit]
user@gladius# show groups member1-re1 virtual-chassis
preprovisioned;
traceoptions {
file VCCP size 100m;
flag all;
}
heartbeat-address 10.4.2.210;
heartbeat-timeout 10;
member 0 {
role routing-engine;
serial-number JN10C7135AFC;
}
member 1 {
role routing-engine;
serial-number JN115D117AFB;
}
If you are done configuring the device, enter commit from configuration mode.
Verification
To confirm that the Virtual Chassis heartbeat connection is working properly, perform these tasks:
- Verifying the Virtual Chassis Heartbeat Connection
- Verifying Use of the Heartbeat Connection During an Adjacency Split or Disruption
- Verifying Virtual Chassis Member Health from Heartbeat Statistics
Verifying the Virtual Chassis Heartbeat Connection
Purpose
Verify that the heartbeat connection between the Virtual Chassis member routers is properly configured and operational.
Action
Display the state of one or both member routers when a heartbeat connection is configured.
{master:member0-re0}
user@gladius> show virtual-chassis heartbeat
member0:
--------------------------------------------------------------------------
Local Remote State Time
10.4.2.210 10.5.3.101 Alive 2014-03-18 10:18:14 PST
member1:
--------------------------------------------------------------------------
Local Remote State Time
10.5.3.101 10.4.2.210 Alive 2014-03-18 10:18:15 PSTMeaning
For each member router, the command output displays
the IP addresses of the local and remote member routers that form
the heartbeat connection. The value Alive in the State field confirms that the primary Routing Engine in the specified
member router is connected and has received a heartbeat response message.
The Time field specifies the date and time of the last
connection state change.
Verifying Use of the Heartbeat Connection During an Adjacency Split or Disruption
Purpose
Verify use of the heartbeat connection when an adjacency disruption or split is detected in the Virtual Chassis.
Action
Display the status of the member routers in the Virtual Chassis:
{master:member0-re0}
user@gladius> show virtual-chassis status
Preprovisioned Virtual Chassis
Virtual Chassis ID: a5b6.be0c.9525
Mastership Neighbor List
Member ID Status Serial No Model priority Role ID Interface
0 (FPC 0- 11) Heartbt JN10C7135AFC mx240 129 Master* 1 vcp-2/2/0
1 vcp-2/3/0
1 (FPC 12- 23) Prsnt JN115D117AFB mx480 129 Backup 0 vcp-2/0/0
0 vcp-5/2/0
Meaning
The Status field for member ID 0 displays Heartbt, which indicates that this member router has used the
heartbeat packet connection to maintain primary role roles during
an adjacency disruption or split in the Virtual Chassis configuration.
The Status field for member ID 1 displays Prsnt, which indicates that this member router is connected to the Virtual
Chassis.
If a router is not currently connected to the Virtual Chassis,
the Status field displays NotPrsnt.
Verifying Virtual Chassis Member Health from Heartbeat Statistics
Purpose
Use statistics collected by the heartbeat connection
to verify the availability and health of each Virtual Chassis member
router. You can also use the show virtual-chassis heartbeat detail command to determine the maximum latency and minimum latency in
your network.
Action
Display and review the statistics collected by the heartbeat connection.
{master:member0-re0}
user@gladius> show virtual-chassis heartbeat detail
member0:
--------------------------------------------------------------------------
Local Remote State Time
10.4.2.210 10.5.3.101 Alive 2014-03-18 10:18:14 PST
Heartbeat statistics
Heartbeats sent: 10079
Heartbeats received: 10079
Heartbeats lost/missed: 0
Last time sent: 2014-03-18 20:03:10 PST (00:00:00 ago)
Last time received: 2014-03-18 20:03:10 PST (00:00:00 ago)
Maximum latency (secs): 0
Minimum latency (secs): 0
member1:
--------------------------------------------------------------------------
Local Remote State Time
10.5.3.101 10.4.2.210 Alive 2014-03-18 10:18:15 PST
Heartbeat statistics
Heartbeats sent: 10083
Heartbeats received: 10083
Heartbeats lost/missed: 0
Last time sent: 2014-02-18 20:03:09 PST (00:00:01 ago)
Last time received: 2014-02-18 20:03:09 PST (00:00:01 ago)
Maximum latency (secs): 0
Minimum latency (secs): 0Meaning
In this example, the number of heartbeat request messages
sent (Heartbeats sent) equals the number of heartbeat response
messages received (Heartbeats received), with no heartbeat
messages lost (Heartbeats lost/missed). This indicates
that both member routers forming the heartbeat connection are available
and operational. Any difference between Heartbeats sent and Heartbeats received appears in the Heartbeats
lost/missed field.
The Maximum latency and Minimum latency fields measure the maximum and minimum number of seconds that elapse
on the local router between transmission of a heartbeat request message
and receipt of a heartbeat response message. In this example, the
value 0 in the Maximum latency and Minimum
latency fields indicates that there is no measurable network
delay caused by this operation. You can use the Maximum latency value to determine whether you need to increase the heartbeat-timeout to a value higher than the default (2 seconds). If the maximum
latency in your network is too high to accommodate a 2-second heartbeat-timeout value, increasing the heartbeat-timeout interval enables you to account for network delay when a Virtual
Chassis adjacency disruption or split occurs.