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20.4R2-S3-EVO: Software Release Notification for JUNOS Software Version 20.4R2-S3-EVO



Article ID: TSB18154 TECHNICAL_BULLETINS Last Updated: 13 Sep 2021Version: 2.0
Alert Type:
SRN - Software Release Notification
Product Affected:
PTX and QFX series running Junos Evolved
Alert Description:
Junos Software Service Release version 20.4R2-S3-EVO is now available for download from the Junos software download site
Download Junos Software Service Release:
  1. Go to Junos Platforms - Download Software page
  2. Input your product in the "Find a Product" search box
  3. From the Type/OS drop-down menu, select Junos SR
  4. From the Version drop-down menu, select your version
  5. Click the Software tab
  6. Select the Install Package as need and follow the prompts
Risk Risk Description
Medium - Action required within next six months Software Release Notification
Impact Impact Description
Low/Notification - Monitor the situation but no action needed Software Release Notification


Junos Software service Release version 20.4R2-S3-EVO is now available.

20.4R2-S3-EVO - List of Fixed issues

PR Number Synopsis Category: "agentd" software daemon
1590432 Non zero values might be displayed against the drop field in ?show network-agent statistics? CLI post switchover scenarios.
In case of switchover scenarios, if the collector which was connected to older master, tries to connect to new master immediately, non-zero values could be seen in drops field for ?show network-agent statistics? CLI. These are not actual packet drops. Each packet sent as part of streaming data would contain a header which would have a meta information of the packet contents. One such field in the header indicates the current packets sequence number. This is a monotonically increasing number for each packet from a producer of telemetry data. During switchover cases, collectors may receive initial packets with a higher sequence number which could get reset to 0 after sometime. Due to this pattern, the cli would show non zero values against drops field. Note: These are not actual packet drops and there is no functionality impact. However it is not expected to see further increase in this value shown against the drops field.
PR Number Synopsis Category: Border Gateway Protocol
1593332 BGP Egress-TE routes lose to BGP routes using the same protocol-preference
In BGP egress-TE scenario, if receiving a BGP route for a peer/128 or peer/32 prefix for which an Egress-TE "ARP" route exists locally, the Egress-TE route is not selected as Active, thus not advertised out to the IBGP core. This PR changes default protocol-preference of Egress-TE ARP route from 170 to 140 to not conflict with BGP and make it better than BGP. Also, this PR changes default protocol-preference of BGP Classful Transport (new feature from 21.1R1 onwards) routes from 169 to 167, to make room for any policy-based maneuvers setting protocol preference.
PR Number Synopsis Category: Express BT PFE L3 Features
1604075 Junos Evolved with IPv6 account, "show interface ae0 extensive" showing large values for input bytes/input packets counters for ipv6 transit statistics
For BT-based platforms, IPv6 statistics show a large value for Input packets/bytes when ipv6 accounting is enabled.
1605599 The host loopback wedge may be detected in PFE when deleting the AE bundle configuration
On Junos Evolved PTX platforms, the host loopback wedge may be detected in PFE when deleting the AE bundle configuration while traffic is flowing, the PFE wedge will cause the traffic to be dropped.
PR Number Synopsis Category: EVO RPD agent PRs
1604549 rpdagent core@NHTable::insert is observer in new primary RE after GRES
The rpdagent process on the primary routing engine may restart after a GRES switch-over event.
PR Number Synopsis Category: Junos Evolved socket replication
1606854 BGP flap might be observed on EVO platforms if NSR is used
On EVO platforms with NSR configuration, BGP is to be in sync between master and backup RE. While backup RE is consuming heavy BGP protocol updates, master RE might send TCP packet with zero window size to the peer device leading to protocol keepalive missing which results in protocol flap. These flaps are intermittent and due to race condition.
PR Number Synopsis Category: Configd, ffp issues
1589858 System logs are not updated when a new user is getting added or old user is getting deleted after commit
On all EVO based platforms using key based authentication, when the existing user config gets deleted or a new user is added the system logs are not updated.
PR Number Synopsis Category: mgd, ddl, odl infra issues
1587646 File copy using FTP does not prompt for password like FreeBSD Junos equivalent. Instead password for FTP has to be part of the ftp:// argument.
When executing a "file copy ftp://" (file copy with FTP URL), Junos EVO does not provide a password prompt like the FreeBSD Junos equivalent. Instead, password needs to be inserted as part of the URL. This PR aims to align Junos EVO with behaviour of FreeBSD Junos, in that the password prompt is provided if password is not provided as part of URL.
PR Number Synopsis Category: Express PFE MPLS Features
1595455 L2VPN stops forwarding when interface encapsulation is changed to vlan-ccc from ethernet-ccc and back
On Evo PTX10003/10003-80c/10003-160c platforms, L2VPN may stop forwarding when interface encapsulation is changed to vlan-ccc from ethernet-ccc and back.
PR Number Synopsis Category: Resource Reservation Protocol
1587704 MBB is not triggered when LSP is reverting back to primary path
From Junos/Junos Evo 20.3X75-D10/20.4R1 releases, MBB behavior for no-cspf LSP has changed to work only if expand-loose-hop knob is configured. If there is bypass LSP to primary LSP switchover in the network, there might be traffic loss due to this issue.
PR Number Synopsis Category: PTX10K specific platform PRs
1608088 Junos EVO : PT10008 : Resiliency improvement - improving individual fan alarm detection and reporting algorithm
On a PTX10008/16 running Junos Evolved software, the system may report and raise RED alarm for an individual fan failure erroneously. This change improves fan failure detection and reporting.
PR Number Synopsis Category: Authentication, Authorization, Accounting, PAM (RADIUS/tacplus)
1600615 The process mgd may crash with authentication setup
If authentication (e.g., tacplus-server, radius-server) is configured on a device, it may fail to open files in a rare case, which may cause the process mgd to crash.

20.4R2-S3-EVO - List of Known issues

PR Number Synopsis Category: EVO Netstack Juniper Tunnel Driver Module
1606822 The TCP connection might be stuck on EVO platforms
On all EVO platforms on which Transmission Control Protocol (TCP) connection is set up with the peer device, if the interface Maximum Transmission Unit (MTU) is configured as a larger value (e.g. MTU 2000 on EVO platform while 1600 on the peer device), when the TCP connection is initiated by the peer, and the TCP maximum segment size (MSS) value is advertised by the peer in SYN packet, however it might be ignored and a wrong (larger) TCP-MSS value is chosen on the EVO platform instead. Due to this issue, TCP connection might be stuck, which will also impact the service provided by the connection.
PR Number Synopsis Category: Express PFE FW Features
1603137 Junos Evolved: ISIS BFD stuck in Init state on FPC restart after RE switchover from RE0 to RE1
When using BFD with ISIS, after a Routing Engine switchover event, the ISIS BFD sessions may stay in the "init" state.
PR Number Synopsis Category: Express PFE L3 Multicast
1529933 SR-TE label with BSID traffic gets dropped in PTX10003. Use the following configuration protocols source-packet-routing no-chained-composite-next-hop.
The SR-TE label with BSID traffic gets dropped in PTX10003 because the chain nexthop is not supported for SR. Please use the work around of disabling the chained nexthop for SR.
PR Number Synopsis Category: PTX10K specific platform PRs
1614952 evo-cda-bt process's memory usage increases by 8 MB per day
The "evo-cda-bt" process adds 8MB of memory to its memory usage per day. The "evo-cda-bt" is a process that runs on a line card of a PTX device running Junos Evolved software.
PR Number Synopsis Category: EVO Services Sflow PRs for defect & enhancement requests
1602448 EVO:: sflow ingress sampling reports oif as 0 and nextHop as 0000:0000:0000:0000:0000:0000:0000:0000 with user ipv6 traffic with ECMP case at last hop router with uhp lsp
Sflow ingress sampling reports oif as 0 and nextHop as 0000:0000:0000:0000:0000:0000:0000:0000 with user ipv6 traffic with ECMP case at last hop router with uhp lsp.
Modification History:
2021-09-13 Update moved PR1606822 from "Fixed" section to "Known Issue" section
First publication 2021-08-24
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