Unified ISSU System Requirements

This section contains the following topics:

• Unified ISSU Junos OS Release Support
• Unified ISSU Platform Support
• Unified ISSU Protocol Support
• Unified ISSU Feature Support
• Unified ISSU PIC Support
• Unified ISSU DPC and FPC Support on MX Series Routers

Unified ISSU Junos OS Release Support

In order to perform a unified ISSU, your router must be running a Junos OS Release that supports unified ISSU for the specific platform. See Unified ISSU Platform Support. You can use unified ISSU to upgrade from an ISSU-capable software release to a newer software release. However, note that:.

• The unified ISSU process is aborted if the Junos OS version specified for installation is a version earlier than the one currently running on the device. To downgrade from an ISSU-capable release to a previous software release (ISSU-capable or not), use the request system add command. Unlike an upgrade using the unified ISSU process, a downgrade using the request system add command can cause network disruptions and loss of data. For more information about the use of the request system add command, see the Junos OS Installation and Upgrade Guide.
• The unified ISSU process is aborted if the specified upgrade has conflicts with the current configuration, components supported, and so forth.
• Unified ISSU does not support extension application packages developed using the Juniper Partner Solution Development Platform (PSDP), more commonly called the SDK.

Unified ISSU Platform Support

Table 9 lists the platforms on which a unified ISSU is supported.

Unified ISSU Protocol Support

Unified ISSU is dependent on nonstop active routing. Table 10 lists the protocols that are supported during a unified ISSU.

Unified ISSU Support for the Layer 2 Control Protocol Process

Unified ISSU supports the Layer 2 Control Protocol process (l2cpd) on MX Series Ethernet Services Routers. In a Layer 2 bridge environment, spanning tree protocols share information about port roles, bridge IDs, and root path costs between bridges using special data frames called Bridge Protocol Data Units (BPDUs). The transmission of BPDUs is controlled by the l2cpd process. Transmission of hello BPDUs is important in maintaining adjacencies on the peer systems.

The transmission of periodic packets on behalf of the l2cpd process is carried out by periodic packet management (PPM), which, by default, is configured to run on the Packet Forwarding Engine. The ppmd process on the Packet Forwarding Engine ensures that the BPDUs are transmitted even when the l2cpd process control plane is unavailable, and keeps the remote adjacencies alive during unified ISSU. However, if you want the distributed PPM (ppmd) process to run on the Routing Engine instead of the Packet Forwarding Engine, you can disable the ppmd process on the Packet Forwarding Engine, by including the no-delegate-processing statement at the [edit routing-options ppm] hierarchy level.

Note: The delegate-processing statement at the [edit routing-options ppm] hierarchy level, which was used to enable the ppmd process on the Packet Forwarding Engine in Junos OS Release 9.3 and earlier, has been deprecated as the ppmd process is enabled on the Packet Forwarding Engine by default in Junos OS Release 9.4 and later.

Unified ISSU enhancements and nonstop active bridging support for the l2cpd process ensure that the new master Routing Engine is able to take control during unified ISSU without any disruptions in the control plane and minimize the disruptions in the Layer 2 data plane during unified ISSU.

Unified ISSU Feature Support

Unified ISSU supports most Junos OS features in Junos OS Release 9.0. However, the following constraints apply:

• Link Aggregation Control Protocol (LACP)—Link changes are not processed until after the unified ISSU is complete.
• Automatic Protection Switching (APS)—Network changes are not processed until after the unified ISSU is complete.
• Ethernet Operation, Administration, and Management (OAM) as defined by IEEE 802.3ah and by IEEE 802.1ag—When a Routing Engine switchover occurs, the OAM hello times out, triggering protocol convergence.
• Ethernet circuit cross-connect (CCC) encapsulation—Circuit changes are not processed until after the unified ISSU is complete.
• Logical systems—On routers that have logical systems configured on them, only the master logical system supports unified ISSU.

Unified ISSU PIC Support

The following sections list the Physical Interface Cards (PICs) that are supported during a unified ISSU.

• PIC Considerations
• SONET/SDH PICs
• Fast Ethernet and Gigabit Ethernet PICs
• Channelized PICs
• Tunnel Services PICs
• ATM PICs
• Serial PICs
• DS3, E1, E3, and T1 PICs
• Enhanced IQ PICs
• Enhanced IQ2 Ethernet Services Engine (ESE) PIC

Note: For information about FPC types, FPC/PIC compatibility, and the initial Junos OS Release in which an FPC supported a particular PIC, see the PIC guide for your router platform.

PIC Considerations

Take the following PIC restrictions into consideration before performing a unified ISSU:

• Unsupported PICs—If a PIC is not supported by unified ISSU, at the beginning of the upgrade the software issues a warning that the PIC will be brought offline. After the PIC is brought offline and the ISSU is complete, the PIC is brought back online with the new firmware.
• PIC combinations—For some PICs, newer Junos OS services can require significant Internet Processor ASIC memory, and some configuration rules might limit certain combinations of PICs on particular platforms. With a unified ISSU:
  • If a PIC combination is not supported by the software version that the router is being upgraded from, the upgrade will be aborted.
  • If a PIC combination is not supported by the software version to which the router is being upgraded, the in-service software upgrade will abort, even if the PIC combination is supported by the software version from which the router is being upgraded.
• Interface statistics—Interface statistics might be incorrect because:
  • During bootup of the new microkernel on the Packet Forwarding Engine (PFE), host-bound traffic is not handled and might be dropped, causing packet loss.
  • During the hardware update of the Packet Forwarding Engine and its interfaces, traffic is halted and discarded. (The duration of the hardware update depends on the number and type of interfaces and on the router configuration.)
  • During a unified ISSU, periodic statistics collection is halted. If hardware counters saturate or wrap around, the software does not display accurate interface statistics.
• CIR oversubscription—If oversubscription of committed rate information (CIR) is configured on logical interfaces:
  • And the sum of the CIR exceeds the physical interface's bandwidth, after a unified in-service software upgrade is performed, each logical interface might not be given its original CIR.
  • And the sum of the delay buffer rate configured on logical interfaces exceeds the physical interface's bandwidth, after a unified in-service software upgrade is performed, each logical interface might not receive its original delay-buffer-rate calculation.

SONET/SDH PICs

Table 11 lists the SONET/SDH PICs that are supported during a unified ISSU.

Fast Ethernet and Gigabit Ethernet PICs

Table 12 lists the Fast Ethernet and Gigabit Ethernet PICs that are supported during a unified ISSU.

Note: Starting with Junos OS Release 9.2, new Ethernet IQ2 PIC features might cause the software to reboot the PIC when a unified ISSU is performed. For information about applicable new Ethernet IQ2 PIC features, refer to the release notes for the specific Junos OS Release.

Channelized PICs

Table 13 lists the channelized PICs that are supported during a unified ISSU.

Tunnel Services PICs

Table 14 lists the Tunnel Services PICs that are supported during a unified ISSU.

ATM PICs

Table 15 lists the ATM PICs that are supported during a unified ISSU. This includes support on Enhanced III FPCs.

Serial PICs

Unified ISSU supports the following 2-port EIA-530 serial PICs:

• PB-2EIA530 on M320 routers with Enhanced III FPCs, and on M120 routers
• PE-2EIA530 on M10i routers

DS3, E1, E3, and T1 PICs

Unified ISSU supports the following PICs on M120, M320, and T320 routers; T640 and T1600 routers; and the TX Matrix router:

• 4-Port DS3 PIC (PB-4DS3)
• 4-Port E1 Coaxial PIC (PB-4E1-COAX)
• 4-Port E1 RJ48 PIC (PB-4E1-RJ48)
• 4-port E3 IQ PIC (PB-4E3-QPP)
• 4-Port T1 PIC (PB-4T1-RJ48)

Unified ISSU supports the following PICs on M10i routers:

• 2-Port DS3 PIC (PE-2DS3)
• 4-Port DS3 PIC (PE-4DS3)
• 4-Port E1 PICs (PE-4E1-COAX and PE-4E1-RJ48)
• 2-Port E3 PIC (PE-2E3)
• 4-Port T1 PIC (PE-4T1-RJ48)
• 4-Port E3 IQ PIC (PE-4E3-QPP)

Enhanced IQ PICs

Unified ISSU supports the following PICs on M120, M320, and T320 routers; T640 and T1600 routers; and the TX Matrix router:

• 1-port channelized OC12/STM4 enhanced IQ PIC (PB-1CHOC12-STM4-IQE-SFP)
• 1-port nonchannelized OC12/STM4 enhanced IQ PIC (PB-1OC12-STM4-IQE-SFP)
• 4-port channelized DS3/E3 enhanced IQ PIC (PB-4CHDS3-E3-IQE-BNC)
• 4-port nonchannelized DS3/E3 enhanced IQ PIC (PB-4DS3-E3-IQE-BNC)

Enhanced IQ2 Ethernet Services Engine (ESE) PIC

Unified ISSU supports the enhanced IQ2 ESE PICs listed in Table 16.

Unified ISSU DPC and FPC Support on MX Series Routers

Unified ISSU supports all Dense Port Concentrators (DPCs) except the Multiservices DPC (MS-DPC) on the MX Series routers. However, unified ISSU does not support either of the FPCs (FPC type 2, MX-FPC2, and FPC type 3, MX-FPC3) on the MX Series routers. For more information about DPCs and FPCs on MX Series routers, see the MX Series Ethernet Services Router Documentation at http://www.juniper.net/techpubs/ en_US/release-independent/junos/ information-products/pathway-pages/mx-series/.

Related Topics

• Unified ISSU Concepts
• Unified ISSU Process on the TX Matrix Router
• Before You Begin
• Performing a Unified ISSU