OSDOCS-12060: updates for CIDR ranges due to masquerade subnet change

Author: JoeAldinger

modules/nw-operator-cr.adoc

@@ -327,6 +327,10 @@ If you set this field to `true`, you do not receive the performance benefits of
 |`string`
 |
 The masquerade IPv4 addresses that are used internally to enable host to service traffic. The host is configured with these IP addresses as well as the shared gateway bridge interface. The default value is `169.254.169.0/29`.
+[IMPORTANT]
+====
+For {product-title} 4.17 and later versions, clusters use `169.254.0.0/17` as the default masquerade subnet. For upgraded clusters, there is no change to the default masquerade subnet.
+====
 
 |====
 
@@ -340,6 +344,10 @@ The masquerade IPv4 addresses that are used internally to enable host to service
 |`string`
 |
 The masquerade IPv6 addresses that are used internally to enable host to service traffic. The host is configured with these IP addresses as well as the shared gateway bridge interface. The default value is `fd69::/125`.
+[IMPORTANT]
+====
+For {product-title} 4.17 and later versions, clusters use `fd69::/112` as the default masquerade subnet. For upgraded clusters, there is no change to the default masquerade subnet.
+====
 
 |====
 

networking/cidr-range-definitions.adoc

@@ -23,6 +23,8 @@ endif::[]
 [IMPORTANT]
 ====
 OVN-Kubernetes, the default network provider in {product-title} 4.14 and later versions, uses the following IP address ranges internally: `100.64.0.0/16`, `169.254.169.0/29`, `100.88.0.0/16`, `fd98::/64`, `fd69::/125`, and `fd97::/64`. If your cluster uses OVN-Kubernetes, do not include any of these IP address ranges in any other CIDR definitions in your cluster or infrastructure.
+
+For {product-title} 4.17 and later versions, clusters use `169.254.0.0/17` for IPv4 and `fd69::/112` for IPv6 as the default masquerade subnet. These ranges should also be avoided by users. For upgraded clusters, there is no change to the default masquerade subnet.
 ====
 
 [id="machine-cidr-description"]