Cisco cmts cBR8 ISIS Configuration on 17.6.1x

[BorislavPenchev0962]

Hi all,

we have Cisco cmts cBR8 ISIS Configuration using IPV6 ISIS Protocol per Level 1 but seems is different now on the new 17.6.1x
till now ISIS router was configured as follows:

rs#show run | s router isis
ipv6 router isis dc-maw
ipv6 router isis dc-maw
router isis dc-maw
net 123.1234.1950.1924.7234.00
metric-style wide
no adjacency-check
set-overload-bit on-startup 180
no hello padding multi-point
no hello padding point-to-point
log-adjacency-changes
address-family ipv6
no adjacency-check
set-overload-bit on-startup 180
redistribute connected metric 20 level-1
redistribute static metric 20 level-1
summary-prefix 2001:2003:7000::/36 level-1

we need the redistribute option above, but on Version 17.6 cmts, we could not find that config:

rs#conf t
(config)#router isis dc-maw
(config-router)# address-family ipv6
(config-router-af)#red
(config-router-af)#redistribute con
(config-router-af)#redistribute connected me
(config-router-af)#redistribute connected metric 20 ?

Default is already the Level-2:

cmts-che#show ipv6 protocols
IPv6 Routing Protocol is *connected*
IPv6 Routing Protocol is *application*
IPv6 Routing Protocol is *ND*
IPv6 Routing Protocol is *isis dc-maw*
Interfaces:
Port-channel1
Port-channel2
Bundle1 (Passive)
Loopback0 (Passive)
Redistribution:
Redistributing protocol connected with metric 20 at level 2
Redistributing protocol static with metric 20 at level 2
Address Summarization:
L1: 2001:2005:AF5F:4::/64 not advertised
L1: 4003:aaaa:4000::/34 not advertised
IPv6 Routing Protocol is *static*

It is currently not clear to me how the cBR8 can now learn/redistribute the routes via level-1?
in internet l could find only the previous configs but not for Version 17.6 ?

Regards

Boris

[Georg Pauwen · Accepted solution]

Hello,

I found the bug below. It seems related, but I am not really sure what is supposed to be done about it...

Handling level for redistribution command in ISIS
CSCvv26782
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Description
Symptom:
1. When non-ISIS protocol routes were redistributed into ISIS protocol, the option to specify levels "was present". It was incorrect and has been removed now.

Router(config-router)#redistribute static ip ? << level option for non-ISIS source protocol
level-1 IS-IS level-1 routes only
level-1-2 IS-IS level-1 and level-2 routes
level-2 IS-IS level-2 routes only
metric Metric for redistributed routes
metric-type OSPF/IS-IS exterior metric type for redistributed routes
route-map Route map reference

2. When one ISIS instance was redistributed into another ISIS instance, the option to specify levels "was not present" and has been made available now.

Router(config-router)#redistribute isis 99 ip ? << No level option for IS-IS source protocol
metric Metric for redistributed routes
metric-type OSPF/IS-IS exterior metric type for redistributed routes
route-map Route map reference

Conditions:
No conditions required

Workaround:
No workaround

Further Problem Description:
The CLI options and behavior have been corrected.
1. Options for level NOT available when redistributing non-ISIS protocol into ISIS protocol

R1(config-router)#redistribute bgp 56 ip ?
metric Metric for redistributed routes
metric-type OSPF/IS-IS exterior metric type for redistributed routes
route-map Route map reference

2. Options for level available when redistributing one ISIS instance into another ISIS instance

R1(config-router)#redistribute isis 2 ip ?
level-1 IS-IS level-1 routes only
level-1-2 IS-IS level-1 and level-2 routes
level-2 IS-IS level-2 routes only
metric Metric for redistributed routes
metric-type OSPF/IS-IS exterior metric type for redistributed routes
route-map Route map reference

[BorislavPenchev0962]

l am also not sure since there is no workaround how to proceed, but

during the Update l've noticed the following messages:

##
Restarting LC in slot (0), as it is being added as a Secondary to LCRED group (0).
redistribute connected metric 20 level-1
^
% Invalid input detected at '^' marker.

redistribute static metric 20 level-1
^
% Invalid input detected at '^' marker.
##



as result all Modems of the Systems does not get iPV6-Address (V6-connection DHCP-Server)

any ideas if this is really fixed on the listed releases as we already tried with 17.6.1x and issue was the same ?

Regards

Boris

[Georg Pauwen]

Hello,

17.6.1 is listed as both an affected, as well as a fixed release (see screenshot).

[Harold Ritter · Accepted solution]

Hi @BorislavPenchev0962 ,

The bugid @Georg Pauwen referred to seems to be the one that explains the behavior changes you are seeing. The purpose of this bugid was to change the semantic of this command, not to allow the level when redistributing routes from external protocol into ISIS. Setting the level should normally be to specify the source level and should only be permitted when redistributing from another isis process.

To fix you issue you can configure a route-map to specify in which level you would like to redistribute the static and connected routes.

route-map setLevel permit 10

set level level-1




router isis dc-maw

address-family ipv6 uni

redistribute connected metric 20 route-map setLevel

redistribute static metric 20 route-map setLevel

This will redistribute your static and connected routes in the level-1 as you want.

Regards,

[BorislavPenchev0962]

example config has worked:

#show ipv6 protocols

IPv6 Routing Protocol is "connected"

IPv6 Routing Protocol is "application"

IPv6 Routing Protocol is "ND"

IPv6 Routing Protocol is "isis dc-maw"

  Interfaces:

    Port-channel1

    Port-channel2

  Redistribution:

    Redistributing protocol connected with metric 20 at level 2 route-map SETLEVEL1

    Redistributing protocol static with metric 20 at level 2 route-map SETLEVEL1

  Address Summarization:

    L1: a.a.a  advertised with metric 20

IPv6 Routing Protocol is "static"




sh isis database l1 detail also showed correct results!

thanks for this idea.

Best Regards

Borislav