| 
                                 Feature  | 
                            
                                 Product  | 
                            
                                 Release introduced  | 
                        
|---|---|---|
| 
                                 IS-IS hello padding (ability to disable)  | 
                            
                                 5320 Series  | 
                            
                                
                                 Fabric Engine 8.6  | 
                        
| 
                                 5420 Series  | 
                            
                                
                                 VOSS 8.4.2  | 
                        |
| 
                                 5520 Series  | 
                            
                                
                                 VOSS 8.2.7  | 
                        |
| 
                                 5720 Series  | 
                            
                                
                                 Fabric Engine 8.7  | 
                        |
| 
                                 7520 Series  | 
                            
                                 Fabric Engine 8.10  | 
                        |
| 
                                 7720 Series  | 
                            
                                 Fabric Engine 8.10  | 
                        |
| 
                                 VSP 4900 Series  | 
                            
                                 VOSS 8.2.7  | 
                        |
| 
                                 VSP 7400 Series  | 
                            
                                 VOSS 8.2.7  | 
                        
To detect maximum transmission unit (MTU) mismatches, Intermediate System-to-Intermediate System (IS-IS) pads hello packets to the full interface MTU. All hello packets on Fabric Extend network-to-network interface (NNI) links are padded . On non-Fabric Extend point-to-point NNI links, hello packets are padded until a hello packet is received from the other side.