Load Balancing RADIUS - Cisco ISE

Seem to be missing a few comment markers, try below

# ISE persistence iRule based on Calling-Station-Id (MAC Address) with fallback to NASIP-Addressas persistence identifier
when CLIENT_DATA {
     #0: No Debug Logging 1: Debug Logging
    set debug 0
 
     #Persist timeout (seconds)
    set nas_port_type [RADIUS::avp 61 "integer"]
    if {$nas_port_type equals "19"}{
    set persist_ttl 3600
    if {$debug} {set access_media "Wireless"}
    } else {
    set persist_ttl 28800
    if {$debug} {set access_media "Wired"}
    }
 
     #If MAC address is present - use it as persistent identifier
     #See Radius AV Pair documentation on
 
    if {[RADIUS::avp 31] ne "" }{
        set mac [RADIUS::avp 31 "string"]
 
        # Normalize MAC address to upper case
        set mac_up [string toupper $mac]
        persist uie $mac_up $persist_ttl
        if {$debug} {
                 set target [persist lookup uie $mac_up]
                 log local0.alert "Username=[RADIUS::avp 1] MAC=$mac Normal MAC=$mac_up MEDIA=$access_media TARGET=$target"
           }
 
    } else {
        set nas_ip [RADIUS::avp 4 ip4]
        persist uie $nas_ip $persist_ttl
        if {$debug} {
                 set target [persist lookup uie $nas_ip]
                 log local0.alert "No MAC Address found - Using NAS IP as persist id. Username=[RADIUS::avp 1] NAS IP=$nas_ip MEDIA=$access_media TARGET=$target"
           }
    }
  }